EFFECT OF STUMP LIFTING ON SPROUTING AT THE REGENERATION SITE

Transcription

1 EFFECT OF STUMP LIFTING ON SPROUTING AT THE REGENERATION SITE NSFP-seminar: Forest regeneration and bioenergy , Vantaa Markus Strandström Metsäteho Effect of Stump Lifting on Sprouting at the Regeneration Site 1

2 Stump lifting - background Stump lifting for bioenergy was started in 2000 and has increased rapidly (2 500 hectare in 2005) Stumps are renewable energy source, substitute fossil fuels and decrease CO 2 emissions. Support the aim to increase use of bioenergy (Finland's National Forest Programme) Several positive effects on silviculture: improve conditions for mechanized planting reduce breeding spots of Hylobius weevil prevent root-rot Share of disturbed soil surface bigger than in conventional soil preparation methods? more natural broadleaves? further management and additional cost? Effect of Stump Lifting on Sprouting at the Regeneration Site 2

3 Metsäteho s project Objective to examine effect of stump lifting on emergence of natural broadleaves at the regeneration site Base indirect approach: stands on stump lifting areas too young Realization inventory: share of disturbed soil surface on stump lifting areas inventory: number of natural broadleaves and share of disturbed soil surface on soil preparation sites estimate: effect of disturbed soil surface coverage on emergence of natural broadleaves Inventories in 2003 Effect of Stump Lifting on Sprouting at the Regeneration Site 3

4 Data Stump lifting sites 10 areas Jämsänkoski district (slides 5 6) Soil preparation trial 7 areas, 9 soil preparation method spruce stands, 9-years old, no tending of seedling stands herb-rich mineral soil and fresh mineral soil forest sites (OMT/MT) Tampere Keuruu region (slides 7 10) Effect of Stump Lifting on Sprouting at the Regeneration Site 4

5 Share of disturbed soil surface on stump lifting sites 100 % 90 % 80 % 70 % 60 % 50 % 40 % disturbed soil undisturbed soil 30 % 20 % 10 % 0 % * Stump lifting site * average Effect of Stump Lifting on Sprouting at the Regeneration Site 5

6 Share of disturbed soil surface on stump lifting sites 100 % 90 % 80 % 70 % 60 % 50 % 40 % 30 % hummock flat hollow humus undisturbed soil 20 % 10 % 0 % * Stump lifting site Categories hummock hollow, soil surface bare mineral soil or mix of mineral soil and humus * average Effect of Stump Lifting on Sprouting at the Regeneration Site 6

7 Number of natural broadleaves on soil preparation trials by soil preparation track Natural broadleaves / hectare Undisturbed soil Hollow Flat Hummock Effect of Stump Lifting on Sprouting at the Regeneration Site 7

8 Number of natural broadleaves on soil preparation trials by soil preparation method Natural broadleaves /hectare 0 No soil preparation Scarification Harrowing shallow Harrowing deep Inverting Mounding - laikku Mounding/scarification Mounding shallow - nav. Mounding deep - nav. Effect of Stump Lifting on Sprouting at the Regeneration Site 8

9 Number of broadleaves on soil preparation trials Undisturbed soil Hollow Flat Hummock Natural broadleaves / hectare 0 No soil preparation Scarification Harrowing shallow Harrowing deep Inverting Mounding - laikku Mounding/scarification Mounding shallow - nav. Mounding deep - nav. Effect of Stump Lifting on Sprouting at the Regeneration Site 9

10 Number of natural broadleaves on regeneration site - estimate Natural broadleaves / hectare Soil preparation site Sites, average Estimate Disturbed soil surface, % Effect of Stump Lifting on Sprouting at the Regeneration Site 10

11 Conclusions I: natural broadleaves on stump lifting sites More disturbed soil surface on stump lifting sites v. conventional soil preparation sites, 65-90% v % (max. 50%) Number of natural broadleaves doubles on disturbed soil surface v. undisturbed soil surface number of broadleaves 30-50% higher (assumption: disturbed soil surface increases 20 80%) Result describes phenomenon, direction and level Number of broadleaves not totally given development of stump lifting method working method education Additional costs? - not calculated Tending of seedling stands in early phase and mechanization! Effect of Stump Lifting on Sprouting at the Regeneration Site 11

12 Conclusions II: natural broadleaves on stump lifting sites Number of natural broadleaves is not merely depending on coverage of disturbed soil surface differences between regeneration areas difficult to explain Other possible factors? site type, soil fertility moisture grass elk grazing number of seeding trees Metla s project Improvement of management of young stand starts in 2007, sub-study: Emergence of natural broadleaves on stump-harvested area Effect of Stump Lifting on Sprouting at the Regeneration Site 12

13 2 different herb-rich mineral soil forest sites stems/ha stems/ha Effect of Stump Lifting on Sprouting at the Regeneration Site 13