11. Genetics in forest practice in Sweden

W. PLYM FORSHELL

W. PLYM FORSHELL is Divisional Chief, Royal Board of Forestry, Stockholm, Sweden.

Summary

At the beginning of this century foresters in Sweden began some remarkable experiments with Scots pine seed and almost 30 years later their research resulted in directives for the transfer of reforestation material in both latitude and elevation. This provenance research has become of increasing importance as it deals with indigenous races and also with the transfer of seed from the continent of Europe. Norway spruce of central European origin brought to Sweden and used within reasonable latitudinal limits has shown considerable growth. The vital point of resistance to frost is a consequence of natural selection and is part of the genetic nature of the population.

Investigations and discussions during the 1930s regarding the question of the influence of heredity and environment on the phenotype of forest trees and stands led to the idea of tree improvement by breeding.

Tree improvement could be obtained by more selective routine seed collection in natural stands and by breeding based on individual selection of the most superior phenotypes, called plus trees.

An inventory of good stands for use as seed sources was begun in the early 1940s by the two existing private organizations for forest tree breeding and by the National Board of Private Forestry. Plus trees were selected for seed orchards. Directions for seed collection were issued by the National Board for the County Forestry Boards, which are the main seed dealers. The version of these directions that was published in 1950 is still adequate.

The Co-ordination Committee for Forest Tree Breeding and Genetics was appointed in 1949. This has developed into a central organization for program discussions. It has been authorized to make rules and procedures for the selection of plus trees, the planning and formation of seed orchards, and the rules and plans for progeny testing.

The committee has been granted subsidies from public funds totaling S kr 3.5 million (about U.S.$700,000).

Seed orchards are now being established to national plan, which calls for a total area of 853 hectares (2,107 acres) of which rather more than 500 hectares (1,235 acres) have been established, the remainder to be completed within 5 years. The orchards will reach full seed production in about 25 years, and the annual total crop is estimated to be about 15 tons of coniferous seed. This is 60 percent of needs.

Routine seed collection from natural stands is still of great importance. The quantity needed manually is 20 to 25 tons. This will fall to some 10 tons as the crop from the seed orchards increases.

Because of the periodicity of good seed years, seed collection often assumes the character of a campaign or "cone-rush." The control of origin is still inadequate when set against present knowledge of population genetics. In addition, all commercial forest tree breeding must be officially controlled.

These are the main reasons why the National Board of Private Forestry, on the instructions of the Government of Sweden, presented a report in 1962 on quality control of forest seed and seedlings. A new Seed Act is proposed and the Co-ordination Committee is to be converted into a Forest Seed Committee appointed by the Government to advise the National Board for Private Forestry on all matters concerning tree seed, seed orchards, progeny tests, and so on.

Chapter 11

Although artificial regeneration has been used in Sweden for some 200 years, the use of selected provenances was not seriously considered until about 80 years ago. At the turn of the century considerable concern was felt in Sweden about the common occurrence of degenerated stands of Scots pine, Pinus sylvestris, which were fit only for fuel. Their origin was described as "European-continental." The seed was imported by private seed-dealers; it was sometimes mixed with indigenous seed which, in turn, consisted of whatever was available at the cheapest price.

This state of affairs called for research. As early as 1882 the Board of Forestry had officially warned the districts of the State Forest Service against using foreign seed. Nevertheless, Swedish foresters still used considerable quantities of imported seed and, during the period 1890 to 1909 for example, some 25 tons of foreign seed were imported.

In 1902, the Swedish Forest Research Institute was founded and in the following year the first provenance project was planned.

In 1905, the first general Forest Conservation Act in Sweden came into force and the County Forestry Boards were established. The Act prescribed that reforestation was compulsory after felling, and a special Order regulating the boards' activities laid down that, among other duties, it was the task of the boards "to promote private forestry by supplying forest seed and seedlings." In 1923, this simple wording of the Order was changed to read:" to make arrangements for a satisfactory sup ply of forest seed and seedlings the quality of which has been controlled and which are suitable for the locality." However, these directions were a little ahead of their time, as there was still not enough information about indigenous provenances in Sweden to permit adequate control of forest seed.

The researches of Wibeck, Schotte and Eneroth resulted in the 1920s in more definite directives for the transfer of reforestation material in terms of both latitude and altitude. This line of research was resumed in the mid-1930s by Olof Langlet who in 1945 introduced a practical scheme for transferring from its place of, origin reforestation material particularly adapted to northern Sweden and its varying altitudes. This scheme was a refinement of earlier results though still partly based on them. In 1957 Langlet revised his scheme.

In the meantime, attention was given to questions of heredity and the possibilities of forest tree breeding. The famous geneticist professor Nilsson-Ehle, who was also concerned with forestry, once said that forest geneticists should consider themselves very fortunate in still having at their disposal the entire range of variation in natural forest populations.

The Forest Tree Breeding Association was founded in 1936, and a few years later the Society for Practical; Forest Improvement began its activities. These two organizations, with Professor Nils Sylvén and Dr. Bertil Lindquist respectively as their scientific leaders, were most active in disseminating the new principles and also initiated or carried out important investigations which greatly enriched the incomplete knowledge of Swedish forest populations. These two experts, ably assisted by their highly-trained fellow scientists, laid the foundations on which the practical work could be built.

Although there were some differences of opinion, the vigorous expression of varying points of view and the indications provided by the field trials attracted the attention of many people and aroused their interest.

In 1941, the National Board of Private Forestry was established as the new civil service department and became the principal body in the organization of the County Forestry Boards. These County Forestry Boards already had a so-called Central Commit tee for maintaining contact with the Government. In the late 1930s this committee began an inventory of high-quality stands of Pinus sylvestris in 5 different counties. The stands were selected in accordance with special instructions and were later carefully tested by experts. The result was the first series of good Scots pine stands classified according to their fitness for seed collection. From the outset the newly established National Board of Private Forestry worked in very close collaboration with the State Forest Service, the Forest Research Institute, the Forest Tree Breeding Association, the Society for Practical Forest Improvement and individual research workers. The characteristic feature of the 1940s was the effort made to introduce new directives for seed collection in natural stands. This new approach implies the application of sound principles of population genetics.

The County Forestry Boards became in due course the main producers of forest seed and seedlings. This fact is of great importance because it constitutes a highly effective administrative instrument. Not only could the National Board of Private Forestry discuss these questions at training courses, meetings and excursions, but it could also issue directives to local organizations all over the country. The State Forest Service and the forestry companies followed, of course, the same lines. As a rule, the forestry companies were members of the two tree breeding associations previously mentioned.

In 1943, the National Board of Private Forestry issued Directives for the registration of stands and elite trees¹ suitable for seed collection. It was then evident that the work on the improvement of seed for future forests had to proceed along two main lines: first, a restriction of routine seed collection, usually carried out in logging areas, to stands or trees of good phenotype. Second, large-scale breeding in seed orchards, combined with progeny tests. The seed orchards represented the more distant goal.

¹ "Elite" tree was the former term for "plus" tree.

These directives were soon amended and simplified in accordance with Lindquist's proposal. He recommended that the classification of stands should comprise only three classes: plus, normal, and minus stands. The demarcation of minus areas, which could not be used for seed collection, was, naturally, the most important measure.

The Society for Practical Forest Improvement began by classifying forests in accordance with their fitness for seed collection, and also made an intensified search for plus trees so as to obtain parent trees for seed orchards. The first large-scale orchards were established in the mid-1940s. The idea of seed production in special seed orchards, which had been introduced a long time ago, acquired renewed interest after Dr. Syrach Larsen had applied the technique of grafting to this end in Denmark. The pioneer in this field in Sweden was Holger Jensen, a skilful horticulturist on whom an honorary doctorate was subsequently conferred.

The Forest Tree Breeding Association made comprehensive studies in the field of polyploidy, with the aim of producing triploids of broadleaved species for practical use. Hybridization methods were also included in the program. The classic example of this is the glasshouse product, Swedish x North American aspen, (Populus tremula x tremuloides). In early spring small female flower-bearing branches of Swedish aspen were pollinated in the greenhouse with air-freighted American aspen pollen, resulting, in late summer, in seedlings about 100 centimeters (40 inches) tall in the field. To-day, to take another example, the comparative tests with progeny derived after open pollination from individual plus trees in forest stands, represent some of the most valuable experiments so far made because they demonstrate the importance of selective seed collection, and because they indicate the reliability of Swedish breeding methods.

In 1948, the Department of Genetics of the Swedish Forest Research Institute was established, the primary concern of which is basic research on forest genetics.

On the instructions of the Government in 1947, an investigation was made which resulted in a proposed Bill for the control of trade in forest seed and seedlings. After a change of cabinet ministers, the new Minister for Agriculture stated in November 1948 that he did not intend to present a government Bill on this matter. His reason for this was that the County Forestry Boards were the main producers of forest seed and seedlings and, consequently, that in this respect their activity could be supervised by the National Board of Private Forestry.

Under these conditions the board decided to revise its directives for seed collection and other matters with the assistance of a committee composed of representatives of forest research, administration and practice. The new version of these directives, which was published in 1950, did not cover tree breeding but was restricted to seed collection and trade in forest seed and seedlings.

It may be of interest to quote a short passage from the introduction to the English translation of these directives.

" Forest seed should be collected from trees and stands of good type from the point of view of production and utility. Consequently, it is of importance to know the origin of the material and its other qualities that are important in reforestation. A uniform nomenclature is of special importance for the trade in forest seed and plants.

" It is quite a reasonable demand that consumers of forest seed and plants should always be able to obtain sufficiently accurate information regarding the origin of the material. It will be of considerable advantage if all the producers of forest seed and plants use the same system of classification for stands, trees and seed, as well as for other data of importance for the identification and use of the material."

The directions deal with the following subjects:

Classification of stands for seed collection
Registration and classification of specially selected trees
Classification of forest seed
Possibility of transferring forest seed and seedlings from their place of origin
Collection of forest-tree seed
Trading in forest seed and seedlings.

The new directives were more closely linked with genetic principles than was formerly the case. They contained a farsighted classification scheme for seed, recommended the application of Langlet's scheme for the transfer of reforestation material, and prescribed the data that were to be marked on cone or seed packages at the place of collection. With regard to trade, only the minimum demands that every consumer has the right to expect were made in respect of origin and quality.

Since the establishment of the Department of Genetics of the Forest Research Institute with Professor Åke Gustafsson as head of department, Sweden has one state and two private organizations for forest tree breeding and genetics.

It is not being too critical to maintain that, to some extent, practice anticipated research during the 1940s. The prevailing enthusiasm had given rise to a slight degree of disorder and a tendency to lapse from the straight and narrow path of science. It was necessary to introduce some form of co-operation to include research and experimentation, theory and practice under joint planning so as to insure a mutual exchange of data and avoidance of duplication. To achieve this purpose, the Co-ordination Committee on Forest Tree Breeding and Genetics was appointed in 1949.

This committee has 12 members. Of these, three are appointed jointly by the Royal College of Forestry and by the Forest Research Institute, three by the private tree-breeding associations (the Forest Tree Breeding Association and the Society for Practical Forest Improvement), and one by each of the following bodies: the Board of Crown Lands and Forests, the National Board of Private Forestry, the Federation of the County Forestry Boards, the Association of Sweden's Forest Owners, and the Federation of Swedish Forest Owners' Societies. The scientific leader of the Committee is the twelfth member.

The following extracts from the statutes of the committee provide some idea of its activities:

" The purpose of the committee is to:

(a) promote collaboration between forest organizations and enterprises, and work for an adequate division of effort among organizations engaged in forest tree breeding and genetics;

(b) act as the central organization for program discussions relating to forest tree breeding and genetics, and deal with such parts of regeneration and production research as are connected with forest tree breeding;

(c) carry out phenotype control and registration of plus trees;

(d) act as the central organization for seed orchard activities: in this respect the committee's tasks are to:

approve the planning, location and composition of seed orchards;

carry out and co-ordinate investigations of seed orchard management;

improve seed production;

(e) co-ordinate and control clone and progeny testing of plus trees: the committee's specific tasks are to:

lay down the general lines for testing clones of plus trees and register clone-tested trees;

lay down the general lines for progeny testing, allocate the work, approve the plans for progeny testing and keep a record of the experiments;

lay down the general lines for checking and controlling experiments;

follow the development of clone and progeny tests and insure that the statistical analysis of the material collected is done uniformly and in accordance with prescribed rules, and co-operate in performing technical and scientific work connected with clone and progeny testing;

(f) approve and register plus trees on the basis of the results of progeny testing. "

FIGURE 24. - An experimental plantation of grafts of Pinus sylvestris at Ekebo, southern Sweden.

There is no need to go into more detail concerning the work of the Co-ordination Committee as this is very clearly indicated. However, it may be of some interest to give an account of the committee's contribution to the practical application of genetic principles in routine seed supply and large-scale tree breeding in Swedish forestry.

First, it was considered necessary to make uniform the control of the phenotype of plus trees. Consequently, more complete and detailed directives were drawn up than those previously applied (see Appendix A). The actual control was carried out by the scientific leader of the Co-ordination Committee, Dr. Enar Andersson, and is still proceeding according to the need for new parent trees.

The committee soon realized the necessity to frame rules for the establishment of seed orchards. In order to examine both scientific and practical procedures, the committee considered it essential to establish its own experimental seed orchards (Figure 24) and applied for subsidies from public funds. In 1951, the Riksdag approved a grant of S kr 500,000 (about U.S. $100,000) and prescribed that these activities were to be supervised by the National Board of Private Forestry in close collaboration with the committee.

A long series of scientific and practical questions had to be solved. No organization could be better equipped than the Co-ordination Committee for the discussion of the establishment and management of seed orchards, since its members represented not only science but also practical application and administration.

The fundamental ideas were presented by Åke Gustafsson (1946, 1952) in his papers "Genetics and breeding in forestry" and "Forest tree breeding - a review and a program." In 1950 a general plan for the establishment of seed orchards for the entire country was presented by Enar Andersson, Helge Johnsson and Eric Stefansson. The following year the team of Andersson, Gustafsson and Johnsson published general directions for progeny testing in forestry.

In principle, the committee accepted the plus tree clonal type of seed orchard for the national program but included also other types in its own research program. The clonal orchards are, in general, combined with clone collections (Figure 25) for genotypical observations, progeny testing, pruning experiments, production of scions and other purposes.

The Co-ordination Committee was careful to promote routine seed collection. The classification of stands and regions with populations of good phenotype was intensified in very close collaboration with the two private breeding organizations previously mentioned. These organizations carried out this kind of work not only on their own account, but also at the request of the committee. A thorough inventory has been made for practically the entire country, which has furnished good but still incomplete knowledge of the location of the best natural sources of forest seed. At least, minus stands and regions are demarcated. Northern Sweden, in particular, where the big forest industrial companies are frequently represented, has been well mapped by the Society for Practical Forest Improvement, now under the leadership of Dr. Tore Arnborg.

TABLE. 10 - AREA OF SWEDISH SEED ORCHARDS (IN HECTARES) ¹

	Scots pine	Norway spruce	Larch	Other conifers	Oak	Beech	Total
County forestry boards	238	170	26	6	18	9	467
State forest service	36	41	7	1	4	2	91
Companies	217	64	13	1	-	-	295
TOTAL	491	275	46	8	22	11	853

¹ hectare = 2,47 acres

After 1945 very extensive forest restoration was begun in northern Sweden since most of the virgin forests had been exploited. The seed supply for high altitudes, however, was very difficult to obtain because of the very long intervals between good seed years. Establishment of seed orchards was therefore started in Norrland, the first stage being clonal seed orchards and the second, after progeny testing, elite seed orchards. The seed produced during the first stage can be conveniently collected every year in the seed orchards, which are favourably located from a climatic point of view. On average, the genetic quality of the seed will probably be better than that of the natural seed and, not less important, the physiological quality will be superior to that of natural seed.

For the reasons given above, the activity of the Coordination Committee was extended to cover also the needs of the State Forest Service and the County Forestry Boards, whereas the private breeding organizations mainly planned seed orchards for the forest companies and other private enterprises.

The national plan for seed orchards was completed in detail and the committee could then start on the practical work. Every orchard was given an identity number; the order of formation was determined in accordance with the urgency of seed production. Additional subsidies were granted and they now total S kr 3.5 million (about U.S. $700,000).

Table 10 shows the distribution of seed orchards among owner categories and tree species according to the national plan. Some 500 hectares (1,235 acres) of seed orchards have so far been established. The oldest already yield considerable seed crops.

FIGURE 25. - Eighteen-year-old grafts of Pinus sylvestris at Sundmo in northern Sweden.

Private tree breeding was reorganized in 1959 when the two existing organizations were amalgamated to form the Swedish Tree Breeding Association. Dr. Tore Arnborg is the managing director of the Association, and Dr. Helge Johnsson its chief of research. In this connection, a fund of S kr 10 million (about U.S. $2 million) was established: the interest from S kr 8 million (about U.S. $1.6 million) being intended to cover running expenses. The remaining S kr 2 million (about U.S. $400,000) were set aside to defray the costs of progeny testing of seed orchards but this sum is not sufficient: probably about S kr 5-6 million (about U.S. $11.2 million) are required. Every individual plan for progeny testing is approved by the Co-ordination Committee. The work in connection with progeny testing will be done mainly by the association, except for a small part allocated to the Department of Genetics of the Royal College of Forestry.

In the event of insufficient male flowering in young seed orchards or in clone collections where crossings for progeny testing are under way, it may be necessary to collect pollen directly from the parent trees. This is sometimes impossible as regards seed orchards intended for high altitudes where flowering begins much later than in the orchard itself. Since pollen can be stored without loss of vitality for one or two years, however, it can be collected from the parent trees in question and stored until the next year. A "pollen bank" has been established by the Tree Breeding Association to enable it to organize this work in conformity with the crossing schedules for progeny tests.

As far as conifers are concerned, the Co-ordination Committee has divided the entire country into seed orchard zones in respect of species and such climatic factors as altitude (in northern Sweden) and rainfall. The sets of clones in the seed orchards represent the respective zones. The wood properties of every plus tree are tested before it is included as a clone in a certain orchard. The committee defrays the cost of this testing. In addition, every proposed site for a seed orchard is inspected before approval is given, especially as regards the soil and isolation from foreign pollen. Finally, as soon as the clone-set has been composed by selecting the best plus trees available within the zone in question, the owner of the seed orchard is given a complete layout plan free of charge. Planting can start as soon as the grafts are delivered. In collaboration with the Tree Breeding Association, staff appointed by the committee are always available for consultation concerning all the details of management. The association is often commissioned to carry out the requisite managerial measures.

The remaining Swedish seed orchards, which have not yet been established under the national plan, are scheduled to be completed within 5 years. If this is accomplished, the orchards will reach full seed production in about 25 years' time. The total annual crop then is estimated at about 15 tons of conifer seed. Probably Sweden will still wish to import about 3 tons of seed annually from the European continent, mostly of Nor way spruce, Picea abies, as the country's total needs are approximately 25 to 30 tons each year. Thus, a quantity of 7 to 12 tons has to be collected from natural stands. This is not large compared with the quantities collected during good seed years.

Until the seed crops from the orchards become of greater importance, it will be necessary to collect considerable quantities of seed from natural stands. The present average requirement is about 25 tons per year. This quantity will gradually be reduced to approximately 10 tons. These figures illustrate the importance of routine seed collection. It is necessary to make full use of good seed years and of seed storage facilities during the intervening periods. Because of the marked periodicity of good seed years, large-scale seed collection often assumes the character of a campaign or even a "cone rush." Whatever good intentions the cone buyer may have, the cone collector is very little concerned with genetic principles, his mind being concentrated on large profits. Running a comprehensive forest seed campaign has its difficulties.

The directives for seed collection to which reference was made earlier in this chapter are still adequate, and nothing very serious would happen if it were possible to apply them in detail. Experience shows, however, how difficult this is to accomplish. And yet, without the work of the County Forestry Boards, seed collection might have been at the mercy of unscrupulous business methods. While it is true that the private production of seed and seedlings has been rather inconsiderable in Sweden, it is also true that it has been quite uncontrolled. Until 1960 the production of seed and seedlings by the boards was subsidized by the state. Today this is done entirely on a commercial basis. In 1961, the subsidies which covered the initial high cost of establishing seed orchards - for example, for the purchase of land, soil preparation and grafting - were also discontinued and are now charged to the boards' production account for seed and seedlings. This makes it easier for private producers of seed and seedlings to compete and, consequently, their production is likely to increase (see Figure 26 and Table 11).

In 1958, in an official report on Swedish private forestry, the need for legislation on trading in forest seed and seedlings was discussed. In 1960, the Government instructed the National Board of Private Forestry to prepare a report on quality control of forest seed and seedlings. The National Board presented its report in May 1962. It was proposed that an Act should be passed on "forest seed collecting and trading in forest seed and seedlings, etc." (The Forest Seed Act).

Amendment of the current system was thought to be necessary, first to link routine seed collection still more intimately with the principles of forest genetics and, secondly, the introduction of measures to secure official control of commercial forest tree breeding.

The main provisions of the proposed Act stipulate:

1. The prescriptions shall apply only to producers trading in forest seed and seedlings. In its capacity as the supervisory authority, the National
Board of Private Forestry has the right to prohibit seed collection from what are apparently poor forest tracts or stands. It is the task of the board to specify such tracts or stands.

2. Any person intending to trade in forest seed and seedlings must apply to the National Board of Private Forestry for authorization.

3. Seed collection, on behalf of an authorized seed dealer, must be controlled in the forest region where collection actually takes place. Special supervisors will be appointed for this purpose. The supervisor is responsible for obtaining all the data on the seed, which are required for judging its fitness for use. He will enclose with the seed pack ages a signed certificate in respect of these data and of the quantity collected. The packages (sacks) will have lead seals attached to them. A copy of these certificates will be sent to the County Forestry Board.

4. The National Board of Private Forestry, as the supervisory authority, is entitled to inspect seed agencies and nurseries and to examine stock sheets of seed and seedlings. The dealer is obliged to keep books for the sale of seed and seedlings.

5. Every dealer in forest seed and seedlings is obliged to comply with the directions issued by the National Board of Private Forestry for the control of the origin and quality of forest seed and seedlings;

6. Seed from seed orchards and controlled crossings is called special seed. Such labels may not be used without the permission of the National Board of Private Forestry.

7. As the functions performed by the Co-ordination Committee for Forest Tree Breeding and Genetics have proved most satisfactory and in view of the authoritative position it has acquired, there are very strong reasons for maintaining such an arrangement in the future. The committee, however, has no financial guarantee for its future existence. It is therefore proposed in the Act to convert the Co-ordination Committee into a Forest Seed Committee appointed by the Government, and having practically the same composition and performing the same tasks as the Co-ordination Committee. It is regarded as essential that the National Board of Private Forestry should have a committee of this nature to assist it in making important decisions on forest seed, seed orchards, progeny tests, etc. It is proposed to grant the Forest Seed Committee a considerable measure of autonomy, especially with regard to all questions of a scientific nature. The staff of the Co-ordination Committee can readily be incorporated into that of the National Board of Private Forestry.

TABLE 11. - ECONOMICS OF SEED ORCHARDS

Initial investment					Running costs cost			Total cost = columns 5, 7 and 8
Purchase of		Miscellaneous	Total	Compounded 50th year	Annual average	Compounded 50th year	Cost of progeny tests to year 50	at year 50	discounted to year 0
land	grafts
1	2	3	4	5	6	7	8	9	10
4 000	6 000	1 000	11 000	78 000	100	15 000	18 000	111 000	15 600

Sale value of seed from 21st to 50th year
Price assumed in S kr per kg	Receipts compounded to 50th year	Receipts discounted to year 0
300	252 400	35 500
200	168 300	23 700
130	109 400	15 400
100	84 100	11 800

NOTES:

1. Costs accumulated at 4 percent compound interest, annual yields of seed 15 kg per earlier yields ignored.

2. All costs and returns in Swedish krone per hectare.

3. This theoretical calculation refers to Swedish conditions only.

Part of an 8 to 10-year old seed orchard of Pinus sylvestris on Domsjöänget in northern Sweden, Mo and Domsjö AB.

FIGURE 27. - Control card for plus tree, included in seed orchard and clone tests.

CONTROL CARD FOR PLUS TREES	Volume score 16.2	Quality score + 2.0	Total score 18.2	Tree species Scots pine	Previous tree number	National number BD 4050
Province	Parish			Name of landowner
FS ranger private forest district/ranger district				Address of landowner
Management unit
Locality
Latitude	Longitude	Elevation, m.		Quantity of suitable scions ²		Quality of scions ²
Method of stand establishment
Seed investigations
Grafted				Cone production
Included in clone tests at
Included in seed orchard at
	Comparison trees					The plus tree 161
Age at breast height	No 1 198	No 2 206	No 3 192	No 4 187	Mean 195.75
Volume factors
Height actual 1	19.8	19. 0	21.6	16.2	19.16	23.9
Height at the age of the plus tree	16.1	14.8	18.1	13.9	16.78	23.9
DBH o.b. in mm. actual	325	338	309	306	319.50	369
Double bark thickness in mm.	35	43	32	48	39.50	46
DBH u.b. in mm. actual	290	295	277	258	280.00	323
DBH u.b. in mm. at the age of the plus tree	236	231	232	222	230.25	323
Height to crown 1	10.7	10.0	12.6	6.7	10.00	4.6
Volume dm ³ u.b.	387	360	417	298	363.00	960
Volume score	-	-	-	-	-	16.2

Tree selected by

	Percent from base of Grown	Comparison trees					The plus tree
		No 1	No 2	No 3	No 4	Mean
Quality factors
Circumference in mm.	50	558	688	435	609	572.60	638
Circumference in mm.	75	316	374	253	322	316.25	350
Circumference in mm. upper diam.		765	795	653	742	738.75	705
Crown radius 1	50	2.5	2.7	1.5	2.0	2.18	1.3
Crown radius 1	75	1.4	1.8	0.9	1.2	1.33	1.0
Length of branches 1	50	1.9	2.4	1.3	1.9	1.88	1.1
Length of branches 1	75	1.3	1.7	0.8	1.1	1.23	0.8
Branch angle degrees ³	50	91	86	86	81	85.75	84
Branch angle degrees ³	76	76	74	76	68	73.50	64
Branch thickness in mm. ³	50	37	54	24	41	39.00	29
Branch thickness in mm. ³	75	30	46	17	29	30.50	22
No. of branches per whorl	50	2.5	2.0	2.0	2.5	2.25	2.0
No. of branches per whorl	75	2.0	1.5	1.5	2.0	1.75	2.0
Height to the first dead branch 1		10.7	9.8	8.5	3.5	8.13	4.6
Quality score							+ 2.0
Height of plate bark 1		3.5	3.5	4.5	4.0	3.88	4.0
Crown shape		Wide normal	Wide	Normal	Wide		Narrow

NOTES:

¹ Measured in meters to one decimal place.
² 1, very poor; 2, poor; 3, fair; 4, good; 5, very good.
³ See Table A2.

MISCELLANEOUS INFORMATION:

Composition of stand:... percent pine,... percent spruce,... percent birch.... stocking;... ground vegetation.

Phenotype checked 27 June 1956
The Co-ordination Committee for Forest Tree Breeding and Genetics
Signed: E. ANDERSSON

The proposed Act may seem to be too rigorous. Two points in particular have been discussed, namely, the prohibition of any seed collection in poor and badly shaped stands, and direct control at the collection site. The first point, though fully warranted from a national point of view, could be amended so as to apply only to the collection of seed for sale. Supervision in the actual region where seed collection takes place is, however, a key point. Without such control there will still be uncertainty about the origin of the seed. Such control will not prove too expensive as, in any case, the collection of seed mainly in logging tracts must be abandoned, and efforts concentrated on standing trees in approved seed stands (Figure 27). Collecting forest seed, for example, from felled trees in a comparatively young, thinned stand, is not in accordance with the principles of forest genetics. There is a clear need for scientific control of forest tree breeding, combined with government measures to implement this control.. Another question of importance is the regulation of imports and exports of forest seed and seedlings. Since 1949 no import of such goods can take place without the permission of the National Board of Private Forestry. The board also considers that exports of forest seed and seedlings should require a license because, unfortunately, considerable quantities of Swedish forest seed have been exported to foreign seed dealers and then re-exported to different countries where the seed must be quite useless for forest production. This type of business should not be permitted in any country. Imported forest seed and seedlings are duty-free. Sweden's most important foreign suppliers are Norway, Denmark, the Federal Republic of Germany, Poland and, sometimes, Finland. The possibilities of selecting good provenances have been much improved since Swedish experts have studied the problem thoroughly. Thanks to the good will, co-operation and very efficient organization of seed collection and certification in the countries mentioned, the selection of suitable foreign seed is now carried out on a basis of mutual confidence.

All efforts will be made to adapt the production of forest seed and seedlings to the principles of forest genetics. Without appropriate legislation this will be difficult to some extent. The question whether or not there is to be legislation on the control of forest seed and seedlings in Sweden is still under consideration at government level.

References

ANDERSSON, E., GUSTAFFSON, Å & JOHNSSON, H. 1951. Avkommeprövningen i skogsbrokets tjänst [Use of progeny trials in forestry]. Norrlands Skogsv. Förb. Tidskr., 4: 373-409.

JOHNSSON, H., ANDERSSON, E. & STEFANSSON, E. 1950. Förslag till program for anläggning av fröplantager [Proposal for a program for the development of seed plantations]. Svenska Skogsfören. Tidskr., 48: 188-205.

LANGLET, O. 1945. Om möjligheterna att skogsodla med gran och tall fro av ortsfrämmande proveniens [On the possibilities of raising forest from pine and spruce seed of nonlocal provenance]. Svenska Skogsfören. Tidskr., 43.

LANGLET, O. 1957. Vidgade gränser far förflyttning av tall provenienser till skogsodlingeplatser i Norra Sverige [Wider limits for moving pine provenances to forest sites in northern Sweden]. Skogen, 44: 319.