ICELANDIC TREE SEED COLLECTING EXPEDITION IN CANADA AND U.S.A.*

by
A. Arnason and T. Benedikz
Iceland Forest Service

INTRODUCTION

Iceland is one of the least forested countries in Europe. Only about 1% of the land area bears woodland of any sort, i.e. ca 1 000 km². The naturally occurring woodlands are mainly of scrub birch, scattered and generally of small area. In addition they have been heavily grazed and degraded for centuries, apart from the few areas enclosed by the Iceland Forest Service (IFS) and the Icelandic Forestry Society. Virtually all timber requirements are imported, apart from firewood and some fencing stakes. There is an urgent need for afforestation to produce not only timber but to provide shelter and erosion control and for amenity purposes.

The native flora of Iceland is predominantly Arctic in its affinities. This is because Iceland was isolated from neighbouring lands during and after the Pleistocene Glaciation. When the ice receded the land was colonised mainly by those plant species which had survived in ice-free refuges, necessarily species capable of surviving in cold, harsh conditions. There are only two indigenous tree species, birch, Betula pubescens Enrh. and rowan, Sorbus aucuparia L; only the former forms woodland. After the settlement of Iceland, 874 A.D. onwards, more temperate species were introduced accidentally, in cattle fodder and with the livestock. More recently there have been attempts to enrich the flora by introducing trees and other plants from climatically similar areas such as Alaska, Siberia, North Scandinavia and high mountain ranges in America and Europe, such as the Rockies and the Alps.

The native flora does not represent a climax vegetation for the climate. Lowland Iceland is included in the Boreal Forest Belt by some authorities. As such Iceland would seem able to support a far richer arboreal flora, as is shown by comparable climatic regions in Siberia, Alaska and Scandinavia.

Planned trials of exotics started at the beginning of this century. Among the species then introduced were three Rocky Mountain species, Engelmann spruce (Picea engelmannii Parry), Alpine fir (Abies lasiocarpa (Hook.) Nutt.) and Bristlecone pine (Pinus aristata Engelm.). The seed was from Colorado, but the exact location of the source is unknown. Both these and later introductions of Rocky Mountain coniferous species starting from the 1950's have shown promise in north and east Iceland. The great difference in latitude between Iceland and Colorado does not seem to cause any observable ill effects on the growth of these species. Rather the success of the first plantings of Rocky Mountain species in Hallormsstadur indicates that it is possible to grow Engelmann spruce to small timber size. Experience with species from other mountain ranges, e.g. Siberian larch (Larix sibirica Ledeb.) from the Altai Mtns. and Mountain pine (Pinus mugo var. rostrata (Ant) Hoopes) from the Pyrenees, confirms that there are similarities between certain montane climates at lower latitudes and those of northern, eastern, and possibly inland areas of southern Iceland.

The present expedition, which lasted from 6 August to 28 October 1971, was made possible through the award by FAO of fellowships financed from the United Nations Development Programme. The expedition was planned to include collections in both the Rocky Mountains and the Cascade Range. The Cascades had been relatively unsampled by the I.F.S. as a seed source and it is possible that the greater influence of the Pacific Ocean makes the climate at timber line there more akin to the more maritime regions in Iceland, i.e. the southern and western.

* Note: This condensed version is based on the authors' original mimeographed “Report on the forestry tour of the Icelandic F.A.O. fellows to U.S.A. and Canada, 6th August to 28th October 1971”, January 1972.

OBJECTIVES

1. To collect provenance samples of forest tree species at or near to the timber line along the ranges of the Rocky Mountains and the Cascade Mountains, for use in provenance trials in Iceland. The first priority species were Abies lasiocarpa, Picea engelmannii and Pinus contorta var. latifolia.

2. To gain knowledge of the environmental conditions of timber line forests for comparison with Icelandic conditions.

3. To make contacts with various persons in U.S.A. and Canada who could help in future collections of seed for Iceland.

SEED COLLECTION

The expedition covered sites in the States of Colorado, Montana/Idaho, California, Oregon and Washington in the U.S.A. and in the Provinces of British Columbia and Alberta in Canada. It was organised in two parts, an exploratory tour (12 August – 2 September) to meet local contacts in the U.S. and Canadian Forest Services, to identify collecting sites and to plan the programme of seed collection, and the main collecting tour (3 September – 22 October). It was not possible to include the coastal range of mountains in British Columbia, where access to the timber line is difficult. In the regions where seed was collected, access to timber line was found to be good in Colorado and southern Alberta, but collection less easy in Montana and British Columbia.

Timing of seed collection. The biggest problem was to fit in in each region with the optimum cone ripening time, i.e. September. It seemed that in the northern regions cone ripening was slightly earlier than further south, whilst the chances of heavy snowfall occurring early were also greater. Thus it was decided to start collection work in Canada and to work southwards.

Methods of collection. Methods which were most convenient and permitted by the various authorities were used. Most cones were collected by climbing standing trees or from squirrel caches. In general whole trees were not felled, occasionally tops of trees were felled if no other method was possible.

Seed years. Apart from Engelmann spruce in South Alberta none of the species bore good cone crops. Good seed years at high elevations are few and far between. As seed quality is often correlated with the size of the seed crop it is likely that seed viability is low during poor seed years. Certainly it was noticeable that this year's cones were considerably smaller than the previous year's on most species. Therefore it seems likely that seed viability of the collection may be low. Cone cutting showed that for Engelmann spruce there were ca. 1–5 filled seeds per cut surface on average. The advance planning of a seed collecting expedition to coincide with a better than average seed year is an important factor affecting its success, but is often difficult to achieve.

Species and provenances collected. A summary of the species and provenances collected is in table 2. Detailed information on each collection is in table 1.

It had been intended to collect samples from all tree species which occurred at timber line along the Rockies and Cascades. Three species, Lodgepole pine (Pinus contorta var. latifolia), Engelmann spruce (Picea engelmannii) and Alpine fir (Abies lasiocarpa) occurred in all areas excepting South Oregon and North California. Engelmann spruce was not a timber line species along the Cascades except on east slopes in North Washington and Lodgepole pine is not a true timber line species, but occurs a short distance below it. The major objective was to collect a representative sample of these three species. The collections in the Rockies give a good scatter over their range between Alberta and Colorado, although no collections were made in Wyoming, Utah or south of Fremont Pass in Colorado, nor on the mesas west of the Continental Divide in Colorado.

Collection of other species was determined by their range.

Mountain hemlock (Tsuga mertensii). A major timber line species in the Cascades and in parts of the Rockies west of the Continental Divide. Samples collected in California, Oregon and Montana.

Bristlecone pine (Pinus aristata). Occurs only in Colorado in our collection area and we were able to collect samples at three sites.

Limber pine (Pinus flexilis). In general occurred at timber line only in the southern end of its range. In Montana and Alberta it seemed to be confined to rocky, southern exposures at midelevations. Samples collected from Alberta to Colorado.

Whitebark pine (Pinus albicaulis). One of the major timber line species along the Cascades, northwards from California, and the Rockies in the N. Wyoming/Alberta/B.C. region. It also forms low scrub above the timber line in those regions. However, we were only able to collect in Canada. In Montana and the PNW the cone crop had been poor and had either disintegrated or been eaten by the Clark's nutcracker, Nucifraga columbiana.

Alpine larch (Larix lyallii). One of the timber line species in southern Alberta, southern B.C., Montana and NE Washington. It was most disappointing that we were unable to collect a single cone. The cone crop had been totally destroyed by a severe night frost in July.

Blue spruce (Picea pungens). In our collecting area Blue spruce occurs from Colorado to southern Montana. It is a component of the lower elevation forest (with Ponderosa pine and Douglas fir) and we did not find any stands above 2 850 m, considerably below the timber line.

Other species such as Shasta Red fir (Abies magnifica var. shastensis), Pacific Silver fir (Abies amabilis), Douglas fir (Pseudotsuga menziesii) and Western White pine (Pinus monticola) occurred either over a limited range of our collecting area at timber line or in some places grew close to timber line. Where possible we made collections of these species.

ENVIRONMENTAL CONDITIONS AT TIMBER LINE

Comparatively little weather data is available from timber line stations. What there is shows there are similarities between timber line areas in the Rockies and Cascades and the Icelandic lowlands (see Table 3).

Firstly, growing seasons are short, ca. 90 days (average of 60 frost-free days at Berthoud Pass, Colorado). In Iceland the growing season ranges from 90 – 120 days in the lowlands. July mean temperatures vary from 10.5 – 12°C (10 – 11.5°C in Iceland). At timber line in the Rockies summer maximum temperatures rarely exceed 25°C, but probably the mean maximum summer temperatures are greater than in Iceland. It seems summer temperatures are greater in the Cascades at timber line - which is much lower than at the same latitudes in the Rockies. It has been contended that the lower timber line elevations there are primarily due to the heavier snowfall and presumably the late melt, which would greatly reduce the effective growing season, and the physical effects of the snow pack. Within the Rockies, the elevation of the timber line, as might be expected, decreases steadily from south to north. In Colorado it averages 3 500 to 3 600 m, in southern Alberta 2 100 to 2 300 m.

The precipitation patterns of the Rockies and Northeast Iceland are similar in having relatively low rainfall. Most of it occurs in the winter; while this occurs as snow in North America, this is not necessarily so in Iceland. Also the winters are decidedly colder at timber line in the Rockies and Cascades than in lowland Iceland; the snow lies unmelted there from October until June. This thick snow layer protects the soil from freezing deeply, at least under forest cover. In Iceland snow does not usually lie such a long time and periods of mild weather are frequent, especially in coastal areas and the lowlands of southern and western Iceland. In addition to damage from frost lift, the soil in these parts of Iceland is usually frozen to about 70 cm depth during the winter and small plants often dry out during the windy dry periods of late winter. In this respect the montane climate of the Rockies is more like northern and eastern Iceland, and possible inland areas of the south and west, i.e. cold, definite winters and cool, fairly dry summers.

Another factor is the frequent occurrence of night frosts during the growing season. At high elevations in the Rockies and Cascades night frosts can occur during any month of the year. This is also true in the inland regions of northern and eastern Iceland.

The montane climate of North America differs considerably in one point from Iceland in that light intensity is much greater and summer day lengths shorter. It has been found that the high light intensity has inhibited regeneration of large clear-cut areas in Colorado. Even planting of the clear-cuts can be unsuccessful where there is no advance regeneration or shrub growth. The difference in day length regime has not proved to be of importance for the Rocky Mountain species tried in Iceland, at least for establishment and seed production.

Available figures show that wind speeds are comparable to those of inland areas in Iceland, so that by itself wind is not a limiting factor for montane species. Above the timber line it is likely that wind speeds are greater than in many of the forest plantations in Iceland.

Generally speaking climate is the more important factor in introducing a species into new regions. However soil or biotic influences, such as insects or disease, can be limiting. Vegetation reflects the interaction of climate, soil and biota and obviously is determined further by what species are available. As such the vegetation is of interest primarily as an indicator of site conditions. One impression we had was that at timber line sites in the Rockies the ground vegetation was much more open and less luxurious than in Iceland. Generally Ericaceous species, Vaccinium scoparium, V. myrtillus, Cassiope sp., Phyllodoce sp. were dominant.

We made no soil investigations. However, few if any of the soil types we collected on are similar to Icelandic soils. There the major soil type is derived from basaltic loess and is usually slightly acid and has a very weak structure. Some parts of the Cascades, however, have extensive deposits of recent volcanic rocks. The soils are derived from glacial tills of basaltic origin or from lava. At McKenzie Pass, Oregon, we collected from stands growing over recent basaltic lavas where the soil conditions are probably very similar to the large areas of Post Pleistocene lava fields in Iceland, many of which are barren of vegetation.

LOCAL COOPERATION

The success of the tour was largely due to the excellent contacts we made with members of the U.S. and Canadian Forest Services. During all our visit to North America we received the help of both Forest Services and the use of their facilities. The personal contacts we have made with the Forest Services and private individuals engaged in forestry work are of great value for the I.F.S. for future collections in these regions. In this object we feel the tour has been very successful.

Numerous individual foresters assisted. The research stations which coordinated local contacts were:-

Colorado. The Rocky Mountain Forest and Range Experimental Station, Fort Collins. This station also provided the coordination with other regions in the U.S.A.

Montana. The Intermountain Forest and Range Experimental Station, Missoula.

Pacific North West (Washington, Oregon and California). The Forest Sciences Laboratory of the U.S. Forest Service, Corvallis, Oregon.

Alberta. The Forest Research Laboratory, Canadian Forestry Service, Edmonton.

British Columbia. The Pacific Forest Research Centre, Victoria.

Seed processing. The cones collected in the U.S.A. were cleaned at the U.S. Forest Service Nursery, Mt. Sopris, Colorado and despatch to Iceland was arranged by the Fort Collins Experimental Station. Cones collected in Canada were cleaned at Petawawa Forest Experiment Station, Chalk River, Ontario or by Mr. F.D. Barnard, Western Tree Seed Ltd., Blind Bay, British Columbia.

Table 1. ICELANDIC SEED EXPEDITION SEED LOTS COLLECTED SEPTEMBER/OCTOBER 1971

1 - Seed collected by Rocky Mtn. For. & Ra. Exptl. Station, Fort Collins, Colorado

2 - Seed donated by Intermountain For. & Ra. Expt. Station, Missoula, Montana

3 - Seed donated by Ass. Forest Ranger, US Forest Service, Butte, Montana

-x   Surplus seed of these provenances available in small quantities on request, from: T. Benedikz, Research Forester, Forest Research Station, Mogilsá pr. Brúarland, Iceland

L/O - Lookout
NF - National Forest
NP - National Park

Table 2 - SUMMARY OF THE PROVENANCES COLLECTED

* Pacific North West. Includes California, Oregon and Washington

Table 3 - CLIMATIC DATA FROM REPRESENTATIVE WEATHER STATIONS IN ICELAND AND TIMBER LINE SITES IN THE CASCADES AND ROCKY MOUNTAINS