AIR1-CT92-0143 Northern Conifers in Fast Growing Conditions: A Step Towards an Adequate Wood Supply for Industry

Contacts
Summary Information



To find similar Items, click on a keyword below:
AIR Cluster IX - Forestry : Biotechnology : Plant Genetics : Wood (Lignocellulose)

	Proposal No:	AIR1-CT92-0143
	Date Prepared:	November 1999
	Source:	Final Summary Report 1996

---

Final Summary Report 1996

Introduction

There is a deficit of wood raw material both for processing and consumption within the EU. As part of the Common Agricultural policy it is the intention of the EU to encourage transfer of land from agriculture into forestry. Western Europe enjoys climate which is very suitable for the fast growth of a number of coniferous species. Even so, the forest area of the EU is not likely to increase markedly in the foreseeable future and in order to produce sufficient raw material for the wood using industries it is necessary to increase production of wood per unit of forest area. It is also necessary for industry within the EU to maintain its competitiveness within world markets.

An increase in the production of raw material per unit area can be achieved either through improving the silvicultural management techniques or the use of genetically improved stock. These two disciplines should not be considered in isolation since they are complementary. Systems for increasing productivity must take into account the need to produce raw material with the qualities required by the wood using industries at a competitive price. It is also imperative that full consideration is given to ecological and environmental conditions.

Objectives

The main objective of the project was to propose attractive techniques for plantation forest management to produce an increasing supply of raw material for the wood-using industry. The aim of the project was to determine economically and ecologically appropriate varieties and silvicultural techniques to produce wood with acceptable characteristics. The project focused on the following coniferous species: Norway spruce, Sitka spruce, Douglas fir and Larch. A great deal of research has been carried out on these four species over the last thirty years. These research programmes have concerned both the silvicultural and genetical aspects. The four species have been shown to be fast growing under plantation conditions on good to medium fertility sites and to react positively to intensive silvicultural techniques. They are also the basis of the raw material for many wood using industries in Europe.

Activities

Fast growing conditions can be defined at two levels: stand and tree. At the stand level, fast growing conditions are mostly related to fertility and other site factors. At the individual tree level forest management has a greater influence through the selection of the spacing and thinning regimes and the choice of genetic material. The project was restricted to the examination of material growing on sites of medium to good fertility including abandoned farm land at an altitude below 750m. The silvicultural methods investigated were site preparation, wide spacing, heavy and early thinnings, applied to plantation with rotation length of 50 years or less. The project included the evaluation of material from seed right through to harvesting techniques. In order to address the different aspects included in the proposal, it was divided into the following main interconnected tasks.

Breeding and selection Early tests for growth and quality traits and introduction of new genetic material were carried out to reduce the age of selection of genetically superior trees in order that genetic gain can be more readily realised by commerce and to reduce the cost of genetic testing by investigating the possibility of selections based on fewer, more fertile and homogeneous sites, as well as to determine the degree of genetic relationship that exits between certain economic traits. These activities also aimed to extend the breeding population of Douglas fir using selections made in the Pacific North West of America and to evaluate the possible utilisation of genetically improved Sitka spruce material from Great Britain in France. It also investigated whether there is true hybrid vigour in crosses between European and Japanese larch.

Plants and seeds production Indoor seed-orchards, somatic embryogenesis, nursery techniques (essentially vegetative propagation) and physiological quality of plants were investigated as part of an extensive range of activities that aimed to accomplish the following:

• To enhance and accelerate production of genetically improved seeds both for breeding programmes and commercial utilisation through flower stimulation.
• To investigate the possibility of using indoor containerised seed orchards versus conventional seed orchards.
• To improve the recovery rate of seed from hybrid larch clones by new seed extraction techniques.
• To improve the homogeneity of emblings (the products of embryogenesis).
• To acclimatise the emblings to the greenhouse and after the field conditions.
• To evaluate the phenotypic conformity of the emblings, versus the seedlings growing under the field conditions.
• To define the optimum conditions for raising stock plants to maximise the number of cuttings.
• To study the factors which influence rooting percentage.
• To evaluate the feasibility of a low cost commercial scale propagation system.
• To find effective physiological predictors of planting stock performance.
• To provide information on the most suitable times for undercutting, lifting, storage, and planting.
• To provide a better knowledge of the limits to clonal propagation and find methods to avoid or reduce ageing.

Silviculture To look at spacing and thinning, establish demonstration plots and investigate, harvesting methods. The influence of different spacing on growth, bole form, branching of Norway spruce, Douglas fir and Sitka spruce was investigated, as was the effect of different thinning regimes on stand characteristics and individual tree growth for Douglas fir and Norway spruce. Demonstrations plots were establish for Norway spruce as monoclonal plantations and plantation in mixtures (monoclonal material and common seedlings) as well as for Douglas fir and Sitka spruce using vegetatively propagated families in comparison with standards. In addition the influence of morphological characteristics of Douglas fir and Sitka spruce trees on harvesting productivity in thinning operations was evaluated.

Wood quality and ecosystems To establish the consequences of fast growing conditions on wood quality and on ecosystems through collection of additional data under such conditions. Activities included evaluation of the effect of the decrease, for Norway spruce, on mechanical properties and hence the impact on use for construction of wooden structures. From the environmental point of view, the influence of thinning on light level and flora abundance and composition in the understorey as well as the impact on biological activity of the soil, microbiological respiration activity, earthworms and macro-arthropods abundance were investigated.

Cost benefits analysis This was carried out considering various possible scenarios, as a synthesis of the project, comparing results of different silviculture schedules from a micro economic point of view including integration of parameters such as wood quality and ecological consequences.

Results

The activities resulted in:

• new methodological tools - applicable to different species and countries : this is mainly the case for early tests, physiology of plants, flower induction techniques, indoor seed orchard management, somatic embryogenesis;
• characterisation under different conditions of silviculture, of the effects of the level and planning of investment, the volume and technological characteristics of the products and some important ecological impacts on flora and soils.
• increased collaboration between EU countries as well as numerous publications (including extracts of annual and final reports that are available on request) and demonstrations through extension services.

The results from the specific tasks can be summarised as follows:

Breeding and selection Some progress was made in the fields of early selection possibilities for different economic traits like bud set, bud burst, growth rate, wood density, stem form. Choice of testing sites is confirmed to be determinant to allow an efficient selection. It could be either nursery or farm field site or forest depending on the traits evaluated. Progress was made in relationship between characters such as stem form in larch and lignification. A set of field tests with new genetic material was established extending by approximately 50 ha the Douglas fir European network. Material exchange between EU countries was realised.

Plants and seeds production Significant progress was made in flowering promotion either in classic seed orchards (Norway spruce, Douglas fir) or indoor seed orchards (Sitka spruce, larch, Douglas fir). Indoor containerised seed orchards were established as a reasonable option to accelerate the transfer of new varieties from research to practical afforestation. Operational facilities were established for hybrid larch and Sitka spruce. For hybrid larch seed extraction techniques were improved. Significant progress was made in somatic embryogenesis techniques (homogeneity, acclimatisation). Norway spruce and hybrid larch emblings were planted and evaluated in nurseries. However, further work is required before this very promising technique could be applied industrially. Cutting propagation of selected families or clones is generally considered as costly. Cheaper techniques were evaluated and pilot scale production established for hybrid larch and Sitka spruce. The success of commercial transfer of these techniques depends on training of nursery staff. In general plant quality determines afforestation success, for Douglas fir it was shown that adapted undercutting and storage techniques could improve establishment.

Silviculture It was found that wider spacing promotes bigger branches and, in Norway spruce, lower wood density providing obvious advantages on individual tree growth in diameter and volume as well as in stand stability. Branching influenced by spacing and plants genetics has a negative effect on harvesting operations. This effect can be included in a harvester productivity model. Positive impacts of thinnings on the economics of conifers plantations was demonstrated through the synthesis of numerous experimental results. For example, with early and heavy thinnings, the rotation length of Norway spruce could be reduced to 45 years on medium quality site, while after the first thinning Douglas fir stand density should be around 500 stems/ha.

Wood quality and ecosystems Dimensioning of a wooden structure with extremely fast growing Norway spruce showed that the economics was better than that based on a slow growing stand.

As far as the impact of silviculture methods on components of the forest ecosystem, it was clearly established that the light level in relation to stand dendrometrical characteristics, influenced flora abundance and diversity. The biological activity of soils under conifers stand was confirmed to be better when stands are heavily thinned: microbiological respiration is higher, earth worms double in quantity, macro-arthropods are more numerous and various.

Cost benefits analysis The cost benefit analysis concluded that the profitability of dynamic silvicultures was better that that of traditional practices.

Conclusion

The results from a wide range of forest science resulted in significant progress and resulted in some practical applications and new project ideas, providing reasonable hopes for conifers under fast growing conditions.