Species trials in the interior of northern Sweden

- Evaluation after 20 years

Johan Westin

8 species tested…

Abies lasiocarpa Abies sibiricaPinus sylvestris Picea glauca

Picea marianaPicea abies Pinus contortaLarix sibirica(L.sukaczewi)

Conclusions Good growth performance of

larch – the best? Survival can be improved

- better nursery management- other seed sources?

Stem straightness could become a future problem

Suitable soil types appear to be ”spruce” types

Background 70’s - a predicted future shortage of wood Need to utilize forests in the interior of

northern Sweden How to re-forestate?

- cold climate- low production

Sponsors Sveaskog Holmen SCA Norrbottens och Västerbottens

allmänningsskogar (=community forests) Swedish Forest Agency

Difficult to regenerate

Spring & autumn frosts Frost damages during the

growing period Variable climate -

Frequent occasions with ”destructive” weather

Flat sites, frost prone sites, frost ”pockets”

Vinter/Early spring damages

Short growing season

Long lasting snow coverage - 7-8 months

October 15 May 15

How to improve regeneration?

Fresch clear-cuts Site preparation Well adapted

provenances - growth rhythm

Planting material - seedling size, - planting time - seedlings in ”rest”

Field trials 21 survival trials 5 production

trials

Species & provenances; # per site, # total used

Picea abies (L.) Karst. 1-3 prov./site, 12 used Pinus sylvestris L. 2-3 6 Pinus contorta ssp. Latifolia 2 3 Abies sibirica Led. 1-2 2 Picea glauca (Moench) Voss 1-3 9 Picea mariana (Mill.) 2-4 8 Larix sibirica 2-4 7

(L.sukaczewi) (4 SO, 3 prov.) Abies lasiocarpa (Hook.) Nutt. 1-3 7

Field trial design (example)

Traits assessed on each tree Vitality 0-3 (Survival 1/0) Tree height, dm Stem straightness class, 0-2, Stem stability class, 0-3 Wood quality class, 0-4

Predicted future wood quality based on defects on the main stem. (stem stability considered separately).

Transfer effects Inoptimal seed sources

- three species Limitations on lat.transfer

but… ≥1 provenance/species & trial

Pinus sylvestris>1.1° southward transfer

Pinus contorta <5.1° northward transfer

Picea mariana <1.3° southward transfer Northward►

◄Southward

Good growth performance of Larch

Relatively low survival of Larch

Larch does not have straight stems

Larch stems have high stability

Intermediate stem wood quality

Site type effects Various variables tested

Spruce type?, Soil productivity, South facing?, Soiltype class,Texture class, Moisture class, Soilwater flow?, Slope-degrees?, Wind exposed?, Frostprone?

Larch survival+ spruce types (not pine),soil water flow, no frost sites - high productive soils

Larch height growth+ fine soils (silt, loam), wind exposure- high productive soils

Large variation in survival

Nursery related problems with Larch

Autumn frost damages in the nursery→Short day (SD) treatment

Grey mold (Botrytis cinerea)→plant density & humidity, removal of dead needles

Planting of seedlings in rest → cool room storage →freezer storage

Conclusions Good growth performance of

larch – the best? Survival can be improved

- better nursery management- other seed sources?

Stem straightness could become a future problem

Suitable soil types appear to be ”spruce” types