PART TWO:
OVERVIEW OF THE WORK REALIZED BY THE PROJECT

I. Poplar Introduction and Improvement

1. 1 Ex-situ conservation of Populus simonii

Background: P. simonii is one of the most important native poplar species in Northern China, and it is the only one both frost-resistant and drought-tolerant. However, remaining P. simonii stands and individuals are rapidly disappearing due to the fact that they are being replaced by the better performing clones and the pressure for more agricultural land.

The disappearance of this species will seriously affect the availability of this genetic material to cross breeding programs and reduce significantly their potential to develop new clones, hence the all important need to conserve as much as possible the diversity of this species.

Achievements  by the Project:

• Exploration of the natural range of P. simonii (started in 1992) in North, North West, North East and Central China, and collection of materials (both for vegetative and sexual reproduction) from all these regions

• Propagation in nursery of the collected material (mainly at Naiman)

• Out-planting started in 1994 in ex situ conservation stands (done at Naiman and Tongyu)

The distribution of P. simonii

P. simonii is a native poplar species to China and has a large distribution area: from the northern Heilongjiang Province to the southern Sichuan Province, from the Liaoning Province in the East to the Qinghai Province in the West. It exists now in Heilongjiang, Liaoning, Jilin, Beijing Municipality, Hebei, Shanxi, Inner Mongolia, Shaanxi, Gangsu, Ningxia, Qinghai, Xingjiang, Henan, Shandong, Jiangsu, Hubei, Sichuan and Yunnan.

In North China and East China it is found below 1 000 m above sea level and in the Northwest occasionaly up to 3 000 m above sea level, especially on brook and river banks.

The Project has carried out a thorough reconnaissance of the distribution area of the species in Northeast China(including Heilongjiang, Jilin, Liaoning), Northwest China (four Provinces) and North Central China (2 Provinces). From all these locations cuttings and seeds were collected and included in the P. simonii gene-bank. Careful records were made, especially on some aged trees and excellent individuals. Table 1.1.1 provides information on some of these trees by way of example.

Table 1.1.1 : Characteristics of some remarkable individuals of P. simonii encountered

Province	Region	Age (years)	Height (m)	Diameter (cm)	Crown Width (m)		Remarks
					East- West	North-South
Hebei	Sangyuan Changliangzhai, HuairenCounty	500	19	182	10. 9	15. 4
	Sangyuan Changliangzhai, Huairen County	500	26	180	7. 4	11. 5
	Yangyuan Sanmafang Sanma	450	24. 5	226	30	32
	Pingquan Liuxi Xuezhangzi	200	16. 5	120
	Dapanshi Baijia, Yi County	200	20	120	30	32
	Jinshatan Huaian County	40	Several dozen of individuals
Shanxi	Inyuanyu'erquanjinglin village	350	29. 5	150	23	26	Ming Dynasty
	Suburban, Longwangmiao, Datong City	200	19. 5	159	20	22	1031 m. a.s.l.
	Nanjiao Xiaojiazhai, Datong City	100	18. 5	134	16	20	1054 m. a.s.l.
	Datong Naijiao Jiaocheng School	300	18	121
	Datong Naijiao Jiaocheng School	300	16	123
	Gaohongkou Hongkou Wutai County		30	197	17. 5	16
	Gaohongkou Hongkou Wutai County		33	250	16	18
	Libazhuang Wangjiapu Huairen County	100	20	128	26. 8	26. 2
	Xicongming Temple Xinzhou Wencun	300	17. 5	193	19. 4	17. 6
	Wuxiang Hanbei Wangjiayu	60	26. 6	93	21	19

Collection of P. simonii material and establishment of ex situ gene conservation banks

The long-term breeding plan of the Project started in 1992 with the collection of P. simonii material identified in the above-mentionned reconnaissance and creation of a single tree ex situ collection of all the collected material, at the Xinglongzao Forest Farm of the Naiman Branch, Inner Mongolia (121°14´ E longitude, 43°12´North latitude). The site is on fixed to semi-fixed sandy land, 241 m.a.s.l., with underground watertable at 5 m deep. Included were also other native poplar species such as P. pseudosimonii and some useful domestic and foreign poplar species, including P. deltoides, P. trichocarpa and P. nigra.

From 1994, 498 groups of P. simonii gene resources have been collected from the whole nation.

The gene-bank is divided in a part propagated exclusively by vegetative means (called the T-Bank) and one created from seeds (called the S-Bank). The T-Bank has an area of 17.7 mu (1.2 ha) and the S-Bank of 36.8 mu (2.4 ha).

The T-Bank includes trees originating from countries like the U.S.A. and Canada, and from 27 different counties in China from Jilin, Liaoning, Inner Mongolia, Hebei, Shanxi, Shaanxi, Gansu, Qinghai, XiangJiang.

The S-Bank includes trees reproduced from seeds introduced from France, Belgium and the U.S.A, and from 14 different Chinese counties from Heilongjiang, Jilin, Liaoning, Inner Mongolia, Shanxi and Gansu (See Table 1.1.2)

Table 1.1.2 : Quantitative information on the Ex-situ gene conservation banks (mainly P. simonii)

Growth, tree-form and presence of pest and deseases are continuisly monitored in both Banks.

In the S-Bank 7 superior individuals have been selected and are being propagated and tested in comparison trials. The fastest growing tree of the seven selected-ones reached a diameter at 7 years old of 25 cm with a height of 16.1m. On average, diameter-growth is 3.6 cm per year for these 7 trees.

Starting in 1998, the S-Bank was duplicated to increase the safeguarding of these valuable resources.

Table 1.1.3 : The "T" -collection

Table 1.1.4 : The "S" collection

Need for In situ conservation of P.simonii

There is a tremendous need to structure a workable protection status for the aged P. simonii trees still surviving all over Northern and Central China, in order to conserve the valuable genetic constitution of the species. Especially after the recent experience of three successive years of exceptional dry weather (1989-2001) in the Korqin Sandy Lands (yearly rainfall 190 to 300mm, about half of normal), in addition to the severe winter of 2001 (minus 41°C), the superiority of the species has clearly been put in evidence.

1. 2. Short-Term Clonal Selection Programme

Background: in order to be able to diversify the number of suitable clones available for afforestation, existing clones from many different locations were collected and brought together in a clonal bank, to serve as a reservoir of genetic material to be further screened and selected.

Achievements by the Project:

• Collection in clonal banks of 652 different clones all over the Three-North Region

• Selection of 7 confirmed superior performing clones, adapted to the Korqin, and 11 pre-selected under observation.

Clonal Banks

A total of 652 clones have been collected from China and abroad and were out-planted in the clonal-banks at Naiman and Tongyu Branches. These clonal-banks have become one of the most important for gene exchange and introduction in Three-North Region. Between 1990 and 2001, clones from five Provinces and Autonomous Regions have been included, as well as 120 from abroad (France, Belgium, and Canada). Also collections by the Chinese Academy of Forestry were duplicated in the clonal banks. Chinese origins include Jianping County and Jin County (Liaoning Province), Qiqihaer City (Heilongjiang Province), Baicheng City (Jilin Province) and Datong City (Shanxi Province).

The performance of the collected clones was closely monitored with respect to the following factors: survival rate, growth in nursery, root development, growth in the field, adaptability, resistance to harsh conditions (drought and frost), and resistance to pest and diseases. A detailled database with all the collected information was set-up.

A methodology was developed for the selection of clones from the existing clonal collections adapted to the conditions in the Korqin. A handful of clones, giving outstanding results for the different site categories (mainly site class 2 and 3) have been identified and comparison trials have been established in nursery and in the field. Further larger-scale propagation is under-way to assure availability of planting stock for further distribution and for pilot plantations.

Safeguards for the consolidation and securing of the valuable clone banks at Naiman and Tongyu Branches are under development for their future conservation.

Selection methodology for screening and ranking of clonal performance

The evaluation and selection process is carried out over three phases:

• a preliminary sreening is based on evaluation of five main criteria (diameter growth, frost-, pests- and disease resistance, and form), and three additional criteria (survival, height growth and branch angle)

• after the first screening, the above criteria are quantified and classified according to three levels: A, B and C, being A the best performance and C the worst

• during the third selection phase, selected clones will be actively infected with diseases and pests, exposed to frost and to drought, in order to evaluate their tolerance.

Table 1.2.1 summarizes the selection process and criteria.

Growth is measured by the conventional method of tree measuring, damage from frost is evaluated through observation of the presence and severity of frost-cracks on the stem, pest resistance is evaluated by the presence of stem-borers, such as Anoplophora glabripennis. Diseases resistance is evaluated mainly through the presence of Dothioella gregaria Sall and Valsa sordida.

• A clone qualifies for Grade 1, if survival rate is over 85%, and among the five main criteria, at least 4 are evaluated as Class A, and not more than 1 criterium gets qualification Class B.

• A clone receives Grade 2 if the survival rate is over 40%, and three of the five criteria are evaluated as Class A, and the remainder are Class B, or two criteria are evaluated as Class A and the remainder get Class B.

• All other clones get Grade 3

Grade 1 clones qualify for further propagation and potential use in afforestation.

Grade 2 clones are maintained for further observation.

Grade 3 clones are discarded.

Table 1.2.1 : Multi-factor scoring standard for poplar clonal selection in plantation

dck: diameter of control clone hck: higth of control clone

In 1999, 23 out of 652 clones were selected with Grade 1, but the extreme climatic conditions in the following years (1999-2001) affected some of the selected clones (damage caused by frost). In 2001 the clonal selection was re-done: 7 grade 1 and 5 grade 2 clones out of the previously selected 23 remained (see Table 1.2.2). These clones should be very resistant to drought and frost, after the severe selection they went through.

During the dissemination of these clones it should be stressed that each has its own optimum regarding living conditions and that they should not be planted regardless of the site-classes.

Differences in clonal performances on different sites can be observed. For instance, Faku 1#, Xingcheng, Anza, Bailin 2#, Euromericana 1-M among others grow better where the underground water level is above 2.5 m, on more fertile sites. Under less favorable site conditions, with the underground water level at 3-4m, Xiaohei 8401, Bailin 2#, Heilin 1#, Liaoza 2#, Zhongchiheixiao X, Shanhaiguan among others grow best. Xiaohei 8401, Bailin 2#, Dalinghe 220 and 136 Poplar are drought-resistant, their form is straight and tall and growth is fast. On more fertile sites, their performance becomes even better.

As environmental conditions vary widely over the large Three North Region, some of the clones that were not selected in the Project area (the Korqin Sandy Lands), may hold promise for regions with different conditions. The Project is actively promoting the distribution of these clones to other areas. In this context it is worthwhile to mention the agreement reached with Institutions in the Ningxia Autonomous Region, for the establishment of the selected clones.

Table 1.2.2 : Multi-criteria scoring of Grade1 Poplar Clones:
comparisson between selection and classification done in 1999 and 2001
(only clones with Grade 1 scoring are considered)

* x/y: x is age after establishment; y is total age (including nursery time); both in years.

1.3 Tree Breeding (Long-Term Poplar Improvement Programme)

Background: for many years, Forest Research Institutes at Chifeng City and at Baicheng City, were among the main poplar breeding institutes in Northeast China, and among the 8 Chinese poplar breeding centres where important achievements have been gained in the development of new clones. As a result several of the today most used clones came from these institutes: P. simonii x P. pyramidalis cv Baicheng #41 and Baicheng #2; P. Zheying #3 x P. canadensis cv Zhelin #4; P. x Xiaozhuannica cv. Zhaolin #4 suitable to the environmental conditions in the Chifeng region; P.nigra x P. pyramidalis cv Bailin #1 and Bailin #2.

The aim of the Long-Term Poplar Improvement Programme by the Project, is the creation of completely new clones, obtained through controlled polinisation of poplar species with desirable characteristics. The main species of interest for the project for cross-breeding area are P.simoni, P. nigra, P. deltoides and P. cathayana. The objective of the breeding programme is to create new clones with the following combination of characteristics: frost-tolerant over winter and resistant to early autumn frosts; resistant to spring-droughts and sudden changes in temperature in early spring; well developed root-system, assuring a survival rate in the field of over 90%; pest and disease resistance better than average; yields 20% above the presently used afforestation species/clones, in height, diameter, and volume; well-formed, comparative straight trunks with comparative thin branches; with a high transformation rate of water and nutritients.

Achievements by the Project:

• A tree-breeding plan was established, based on a well-thought breeding strategy;

• 219 inter- and intra- specific crosses implemented,

• 147 crosses succesful and descendants out-planted and raised in nursery

• thousands of new, potentially valuable clones created, and now scrutinised for out-standing characteristics.

The breeding outputs are specified in Table 1.3.1. As may be observed, decendants of the dxs crosses came partially from obtained seeds and partially from tissue culture, as plants were very weak and descendants would not have survived otherwise.

The symbols used are as follows:

• sxs: cross-breeding of P. simoni with P. simonii (from different origins)

• sxn: cross-breeding of P. simonii with P. nigra

• dxs: cross-breeding of P. deltoides with P. simonii

• nxn: cross-breeding of P. nigra with P. nigra (from different origens)

• dxn: cross-breeding of P. deltoides with P. nigra

Table 1.3.1 : Breeding Outputs and follow-up.

Tree Breeding Flow Chart 1998-2001
1. Crossbreeding 1998
Year	s x s	s x n	d x s		n x n	d x n
			from seeds	from tissue culture
1998	1387 individuals are established in nursery, 461 surve, from 14 crosses	1235 individuals are established in nursery, 807 surve, from 10 crosses	683 individuals are established in nursery, 463 survive, from 4 crosses	849 individuals from 8 crosses are established and surviving in nursery	18 individuals established in nursery, 4 survive, from 1 cross
1999	Plants are coppiced in nursery	Plants are coppiced in nursery	Plants are coppiced in nursery	328 individuals are selected to be clonalised (propagation), giving 328 clones	Plants are coppiced in nursery	Some individuals obtained from 3 crosses, none survived
2000	190 individuals from 14 families, are selected (out of 461) and clonalised (propagation), giving 190 clones.	227 individuals are selected (out of 813) and clonalised (propagation), giving 227 clones	Two strategies: a first selection among 50% of individuals within each family results in 155 plants selected, and clonalised; the other 50% is coppiced again	197 individuals are selected (out of 328), and coppiced	Plants are coppiced in nursery
2001	a) 107 clones from 12 families (obtained by keeping the better half of clones from each family) are selected (out of 461 coppiced indiiduals) and out-planted (3+1, rooted stock); added are 2 families with only one or two seedlings (seedling conservation stand) b) 190 clones of 14 families are coppiced c) 93 clones are selected and coppiced	a) 179 individuals are selected from the coppiced 813 individuals are out-planted (3+1, rooted stock; above ground parts pruned-off after planting): seedling conservation stand (1NM2001AF05) b) Pruned-off parts of the above 179 clones, are sent to TY: establishment of nursery comparisson trial c) 125 clones are selected (out of 227, see year 2000) and nursery comparisson trial is established.	a) from the coppiced individuals (463), 91 are selected and out-planted (3+1, rooted stock; above ground part pruned-off after planting): seedling conservation stand b) a second selection is done: out of the 155 selected individuals (done in year 2000), 82 are selected, and established in a nursery comparisson trial (XLZ) c) the pruned-off above ground parts of 91 clones (see under "a" above) are sent to TY for establishment of nursery comparisson trial d) 91clones, selected from 463 individuals were out-planted (3+1, rooted stock): seedling conservation stand. (1NM2001AF05)	a) 78 clones are selected (out of 197); establishment of a nursery comparisson trial (1NM2001NU02) b) a total of 532 individuals of 209 clones (179 clones selected from 328, plus 30 other clones also selected from the 328) are out-planted as (2+1, rooted stock; above ground parts pruned off): seedling conservation plot (1NM2001AF05) c) cuttings from pruned above ground parts of the 179 selected clones sent to ZW, Sheibeitu and Chagintai (FRI Tongliao), Xinjiang, Qiqihaer, Yinshuan, Gai Xian for establishment of nursery comparrison trials	2 individuals selected and out-planted (seedling conservation stand)

Tree Breeding Flow Chart 1998-2001 (Continuation)
2. Crossbreeding 1999
Year	s x s			s x n			d x s			n x n	d x n
							from seeds		from tissue culture
1999	3079 planted,2405 individuals from 15 crosses are established in nursery			4325 planted and 3074 individuals from 30 crosses are established in nursery
2000	Plants are coppiced in nursery			Plants are coppiced in nursery
2001	387 individuals are selected to be clonalised (propagation), giving 387 clones			1137 individuals are selected and clonalised (propagation), giving 1137 clones
3. Crossbreeding 2000 (China and Canada)
	In China								In Canada
Year	s x s		s x n		d x s			n x n	d x n
					from seeds	from tissue culture
2000	2491 planted, 1467 individuals from 19 crosses are established in nursery		5006 planted, 3243 individuals from 37 crosses established in nursery						93 individuals obtained from 6 crosses of chinese nigra with canadian Walker 49 individuals obtained from 4 crosses of chinese nigra with canadian OPW-170H 28 individuals obtained from 2 crosses with Hill
2001	Plants are coppiced in nursery		Plants are coppiced in nursery
4. Crossbreeding 2001 (Canada)
Year	s x s	s x n			d x s			n x n	d x n
					from seeds	from tissue culture
2001									27 ndividuals obtained from 3 crosses of chinese nigra with canadian P. Deltoides

P. deltoides			P. simonii			P. nigra
Introduction of highly compatible females from abroad and crossings done in Canada			Collection of genetic resources from various locations			Introduction from Europe and collection of pollen of with high compatibility
Crossing		Testing of the compatibility of P. simonii from different sources and individuals			Crossing		Crossing
Short-term breeding section of new clones for the Three-North Region		Long-term breeding cultivation of excellent parents of P. simonii			Short-term breeding new Euramerican clones for northern Regions		Short-term breeding selection of new clones for the Three-North Region

Table 1.3.2 provides a summary of the main quantitative results regarding crosses realised (indicated in the table as "done") and succesfull crosses (indicated as "OK").

A total of 219 crosses have been implemented, with 147 succesful results. It should be observed that none of the crosses between P. simonii as male and P. nigra as female have been succesfull, neither the crosses between P. nigra as male and P. deltoides as female.

Thousands of potentially valuable new clones have been created and are being selected according to a rigourous selection methodology (see Table 1.3.3). The selction work is mainly realised at the Naiman Branch.

Table 1.3.2 : Outputs of cross breeding

Species (male) >		P. simonii								P. nigra
		Northwest section			North China section			Northeast section		Xinjiang		Belgium
		Crosses			Crosses			Crosses		Crosses		Crosses
Species (female)	Cross- combination	Done	OK		Done		OK	Done	OK	Done	OK	Done	OK
P. simonii (female)	WN	4	3		8		6	6	5	15	12	7	4
	CN	3	3		3		1	0		8	8	4	4
	EN	13	9		18		16	9		52	44	11	5
Total	Realised (done) crosses: 64 Successful (OK) crosses: 48									Realised ("done") crosses: 97 Successful ("OK") crosses: 77
P. nigra (female)	Xinjian	2	0					10	0
Total	Realised ("done") crosses: 12 Successful ("OK") crosses: 0
P. deltoides (female)	Canada	10	3	4		1		11	3	8	6
	China	4	4					4	4	3	0
Total	Realised ("done") crosses: 33 Successful ("OK") crosses: 15									Realised ("done") crosses: 11 Successful ("OK") crosses: 6

Table 1.3.3 : General selection scheme for clones obtained by cross-breeding

Table 8: Procedure of trials

Table 10: Selection methodology for newly created crosses

1.4 Securing of the Field Stands of the New Clones

Mechanisms for the preservation of this potential extremely valuable genetic material will have to be established untill a final field selection of the obtained clones can be realised (at least 10 to 15 years from now). The securing of the field stands of these new crosses is a priority for the remainder of the Project. A screening of the possibilities is on-going and a draft agreement has been developed.

2. Conifer Introduction, Selection and Afforestation

Background: Pinus sylvestris var. mongolica grows naturally in NE Inner Mongolia, North of the project area. Its resistance to cold and dry conditions makes it an important option to the project in its attempts to increase diversity. However, in the Zhangwu region where the species has been widely planted, it is very prone to attack by Dendrolimus; in Naiman and Molimiao, the high carbonate content of the upper layers of the soil impose restrictions; and in Tongyu salinity-alkalinity impose severe limitations. Furthermore, nursery techniques, both bare-rooted and containerised, have still ample potential for further improvement.

Achievements of the Project: 

• Establishment of provenance trials with 14 different provenances of P. sylvestris var. mongolica

• Establishment of Conifer comparison trials with 21 species, and preliminar selection of P. banksiana and P. sylvestriformis as promising species

• Establishment of afforestation trials with 21 pine species

• Development and implementation of undercutting techniques in bare-root pine nursery and development of mechanised bare-root undercutter

• Replacement by mechanised undercutting of the traditionally transplanting of pines

• Trials on special afforestation techniques for pine, including use of planting tubes, micro-irrigation, rainy-season planting of pines, transplanting of big pine trees

• Fine-tuning of pine nursery techniques (frequency of undercutting, fertilization, application of anti-transpirants, substrate composition, over-winter cold-protection, both for bare-rooted and containerised seedlings...)

• Establishment of a large-scale pilot plantation of P sylvestris var. Mongolica of 2, 000ha in Zhangyu County.

2. 1 History of Conifers in Korqin

The natural distribution of P. tabulaeformis and Juniperus rigida natural forest in the west of Korqin Sandy Lands and Picea mongolica forest near Keshiketeng banner proves that there is a natural foundation for conifer afforestation in the Korqin Sandy Lands. However, due to the degradation of soils and changes in climatic conditions, added to increased human pressure, the over-all conditions for the forests are different from the past. Difficulties for conifer afforestation in the region are big and pose a challenging task for all involved to overcome.

Starting from 1952, the Chinese Academy of Science and the Liaoning Sand Fixation and Afforestation Research started species trials in order to find a species suitable for sand-dune fixation. Among the species tried were Scots pines (Pinus sylvestris var.mongolica), P. tabulaeformis, and broad-leaved species such as Populus pseudo-simonii, elm (Ulmus pumila) and mulberry (Morus alba).

From the late 60's to the early of 70's experimental demonstration plantations were established with Scots pine in the Naiman Banner Railroad Forestry Farm, in Wengniute Banner, in Aohan Banner; and in the suburb of Chifeng City.

After the start of the TNSP, further Scots pine plantations were established in Inner Mongolia in Aohan Banner, Wengniute Banner, Kezuohou Banner, in the Liaoning Province in Zhangwu County, Changtu County and Kangping County and in the Jilin Province in the region of Baichengzi.

2. 2 Conifer species introductions by the Project

Between 1990 and 2001, the Project has introduced at 10 opportunities 21 conifer species, 62 provenances, 134 seedlots.

In 1992, 8 conifers were introduced and established in a nursery trial, including Pinus banksiana, Pinus contorta, Picea mongolica, Picea mariana, Picea glauca, Abies holophylla, Pinus sylvestris var. Mongolica, Pinus sylvestriformis.

In 1992, 14 Pinus sylvestris var. Mongolica provenances were established in a provenance trial. Provenances from Qingshan and Gaofeng outgrow local provenances by 20%.

Between 1993 and 1996 provenance trials of Pinus nigra were established in the different Branches, and Larix sp. were introduced.

Juniperus virginiana was introduced from South Dakota (U.S.A.) in 1995.

In 1998, 13 Pinus banksiana provenances and 5 Pinus contorta provenances were introduced from North America and provenance trials established.

In 1999, Juniperus scopularum (2), Sabina virginiana (1), Picea glauca (2), Picea pungens (2), Pinus ponderosa (2), Pinus contorta (1), Pinus sylvestris (1) and Pinus banksiana (1) were introduced from Colorado and North Dakota (U.S.A.) and established in nursery. In brackets the number of provenances is indicated.

Pinus eldarica was introduced in January in 2001 from Armenia (Northern Caucasus), and Juniperus scopularum was introduced again in March 2001 from Colorado.

Most of the introduced conifer species have adaptation difficulties, and mortality is high after winter, mainly for conifers from western and central Europe, with the exception of Pinus nigra (Austria).

Pinus sylvestris from northeast Europe is resisting and conifers from central and northwest North America are generally surviving well. This is not only because of comparable geographical latitudes, but also because of similar climatic conditions in their region of origin.

2. 3 Species and provenances comparison

Results from comparative species trials done at Zhanggutai and Xinglongzhao indicate that four species may be recommended on a preliminary basis for the Korqin: Pinus banksiana, Pinus sylvestriformis , Picea mongolica and Pinus sylvestris (Northeast Europe and Russian provenances).

Other conifer species that need further observation are Pinus contorta, Pinus nigra , Pinus ponderosa, Juniperus virginiana , Juniperus scopularum, Picea pungens, and Picea glauca.

Scots Pine Provenances

A Scots pine provenance trial was set up in 1992 by the Project at Naiman's Xinglongzhao Forestry Farm, at Tongyu's Xinhua Forestry Farm and at Zhangwu's Zhanggutai Forestry Farm.

After 10 years of observation, results indicate that the provenance of Qingshan and Gaofeng are the best provenances from plantations from unknown origin; and Huma and Tahe are the best provenances from natural forest.

The provenance of Zhanggutai (Liaoning Province) has a life span from 80-100 years at origin (Inner Mongolia Hulunbeir Honghuaerji Sandy Lands), but at Zhanggutai this is reduced to about 60 years. The emergence of Diplodia is reducing the life span of the trees to even 40 or 45 years.

2.4. Nursery techniques

Bare-root Conifer Nursery

Nursery site selection: The conifer nursery should be located on sites not susceptible to inundation, with good drainage and with soil pH about 7.0 or slightly less, with sandy or loamy soil texture, not clayish and not saline. These conditions can be found in the south- east of Zhangwu County and in the south of Kezhuohou Banner. In the central and western parts of the Korqin Sandy Lands, the soil contains Calcium Carbonate causing the pH to be between 7.5 and 7.8, affecting seriously the growth of many conifers, including P. sylvestris var. Mongolica.

Soil improvement in nursery: In Zhanggutai of Liaoning province, the nursery soil for the production of Scots pines (sandy-loamy, pH 7.0) is improved with peat (1500 m³ per ha). In case pH is too high it may be lowered applying sulphur in powder (650 kg per ha) over 5 to 6 years, with simultaneously applications of amonium sulphate as fertilizer, according to experiences in the U.S.A. where pH was lowered from 7.3-7.8 to 6.0-6.5.

Handling of seeds and sowing: origin of seeds: sometimes, the conifer cones are harvested too early and the seeds lack maturity, or seeds are not well cleaned and desinfected and may transmit diseases or pests.

In order to plan correctly for the sowing it is necessary to purify the seeds as a first step: getting rid of impurities and of empty or bad seeds. A simple means for pine seeds is submerging the seedlot in water: bad seeds will float and should be eliminated, the others should be air-dried under shade. A germination test will provide information on the viability of the seeds and on the germination time needed. Many seeds need a special treatment before sowing, such as soaking, stratification (burying the seeds with humid sand) or filing of hard-coated seeds.. Some species germinate slowly or difficultly: they should be sown in between July and November, and covered by a thick cloth permiting ventilation for overwintering and germination in next spring. Seeds that germinate readily should be sown in spring. Before sowing, prepare the soil well, smoothen the bed and apply irrigation. Sowing may be broadcast or in lines, and seed should be covered by a thin layer of sand, about the thickness of the seed itself. Rice straw may be used to cover the sowing-bed, and fine spray irrigation should be applied daily. After germination of two thirds of the sown seeds, the rice straw should be removed and frequency of irrigation gradually reduced.

Raising of the seedlings: After removing the rice straw cover, it is necessary to maintain a certain level of humidity in the beds, but not too much as this will produce fungi. Also, until the germinants shed the seed hull, protection against birds is needed. To avoid damping-off, a common fungus disease in pine germinants, regular applications (every 7 - 10 days) of special anti-fungicides is necessary. Weed control may be done chemically, and fertilisers should be applied two to three times. Regulate the temperature of the seedling bed by the management of humidity and shade.

Winter protection: one-year seedlings traditionally are covered in autumn by soil as protection against winter cold and drying-out. Irrigation is applied to the seedling-bed before covering, and covering soil is removed again in April of the next year.

Transplanting: traditionally, one-year old pine seedlings are transplanted in order to stimulate root growth. Densities used in the transplanting beds are normally 60-70 plants per m² . The two-year old transplanted seedlings are also burried over winter.

Mechanised undercutting: In order to improve the traditionally transplanting technique, which is time-consuming and may cause distortion of the root system, the Project has developed a mechanised tractor-mounted undercutter, inducing abundant and fibrous root-growth in pine seedlings. Undercutting should be done once per year at a depth of 12-13 cm deep, during August. In August of the second year, lateral root-prunig is done manually. The idea is to remove about 30 % of the root-volume, more than this would affect seedling growth. Irrigation should be applied before (to soften the soil) and after (to restore plant-turgescence).

Due to this new technique in the Korqin, two-year old seedlings hve increased 40 to 50 % in growth, and survival rates in the field have increased by 15 to 20 %.

Containerised seedling production in greenhouse

Container selection: containers come in many different materials (hard plastic, soft plastic, paper and compressed peat, among others). The main problem with containers is deformation of the rootsystem, caused by spiralling of the roots. Good containers ("root trainers") should have longitudinal ribs or other devices to reduce the spiralling of the roots, and have one or several holes at the bottom. Paperpots are not adapted for dry climates: the paper decomposes only slowly in the dry sand, and may function as a wick, drying-out the soil even further. Polybags are not recommended.

The size of the containers for the conditions in Korqin should be fairly large, as the plants are not ready in one year for the field. This is a serious handicap for the development of containerised nurseries. Containers should not be placed directly on the soil, but should be suspended on a wire-mesh, avoiding that the roots grow out of the container into the soil. When properly used, when the roots get to the bottom of the container, the root tip grows through the hole(s) at the bottom of the container, coming in contact with open air and dies of.

Substrate for containers: the substrate should have a good water-holding capacity, well ventilated and rich in nutrients. Fibrous peat should make up the main body of the substrate, mixed with perlite, mica and sand. The following mixture has given good results in the Project: peat 70%, phosphate fertilizer 1%, coarse sandy soil or perlite 29%. Generally, the more peat , the better the results. Results were not good when peat-contents was below 50%.

Sowing and management of containerised seedlings: in the greenhouse, starting in February, sow the carefully selected and viable seeds in the containers and cover by a layer of about 3mm (for pines) of perlite and peat. Irrigate frequently in small amounts, to avoid excess humidity that may cause the fungus disease "damping-off". Lowering pH of the substrate reduces the risk for damping-off. Apply fertilizer after one month of growth, dissolved in the irrigation water. From now on, irrigate once a week, or when needed, abundantly (to avoid salinization). Reduce the amount of water over the last ten days of July. In August, move the containers outdoors, and start hardening off procedure (basicly reduction of irrigation); during the first ten days of November, cover for winter with peat or with transparent plastic sheeting.

Control of temperature, humidity and illumination in the greenhouse: for confers, the ideal temperature range in the greenhouse during daytime is 20-28°C; nighttime temperature should be over 15°C; if temperature exceeds 30°C, growth is affected; exceeding 35°C damage is caused and exceeding 40-45°C, the plants start dying off. The plastic sheeting used for the greenhouse should be white and transparent (not blue-ish).

Temperature is regulated by opening the gates to the North and the South; by installing exhaust fans; by raising the sheeting covering the side-walls of the greenhouse; by augmenting shading through covering the plastic sheeting on the top of the greenhouse.

Humidity is regulated by spraying when needed.

2. 5 Conifer afforestation on the sandy lands

Selection of afforestation sites: sites that have natural vegetation (herbs, shrubs) are best, as the exisitng vegetation provides shelter against wind and wind-blasting.

Planting: one of the main problems in Korqin related to tree establishment is the fact that during spring, when plants get out of dormancy after winter, meteorological conditions are very adverse: almost absolute absence of precipitation and very windy, with associated dust-storms. Therefore, traditional planting technique uses deep (30-35 cm) planting holes, to provide shelter and to increase probability of presence of some humidity in the rootzone. Age at planting time is normally 2 years. If soil-humidity is too low, irrigation at planting time should be provided (15 liter per plant).

Protection during selection and transport: bare-rooted seedlings are very susceptible to deshydratation when not properly handled, more so if relative humidity is low. It is essential to take all possible precautions against drying-out of the rootsystem with bare-rooted plants. Seedling roots should be packed in plastic sheeting with mud, and plants should be covered during transport from the nursery to the field.

Selection: due to the fact that most pine nurseries have high densities (to increase revenues, not plant quality), a severe selection should be applied to the seedlings to be out-planted under these difficult conditions, discarding weak, not well lignified plants, or plants with under-average root-system.

Winter protection of out-planted trees: similar to the traditional protection applied in nursery, young trees out-planted in the field are also covered with soil to provide protection against dehydratation and sand-blasting damage. Sands start moving freely on the soil surface at wind speeds of 5 m per second. Speeds of 8 m per second generate full-sized sand-storms. The movement of sand near the surface, produces very strong mechanical impacts on the needles of the young trees. The sand-particules break the epidermis of the leaves, causing dehydration and death. The terminal buds of pines are embedded by resin and are not easyly harmed. However, the dehydration of the leaves will also gradually affect the lateral branches and finally the dehydration of the terminal buds, causing the death of the whole tree. Covering young trees with soil during the first two winters after out-planting in the field increases survival rates by about 10 %.

Planting density: normally a spacing between rows of 3 to 5m is applied and in-row of 2 to 3m. This brings the number of plants per ha to between 1666 and 667 trees. Under the semi-arid conditions of the Korqin the lower densities are best suited.

Inter-cropping is possible during the first 2 to 3 years (depending on the planting density), and helps to reduce competition between trees and weeds. It also provides some income. However, this practice should not be encouraged as soils are left bare from autumn to late spring and wind erosion is favoured.

Weeding: the best way to eliminiate competition but leave enough soil cover to reduce wind erosion is to weed in a circular form around the stem of the trees, with a radius of about 1m. Additional benefits (increase of content of soil organic matter and reduction of evaporation from soil) are gained if the eliminated weeds are arranged on the bare soil around the tree (mulching). Furthermore mulching protects the area around the plant from being blown-out with baring of the roots as consequence.