LONG TERM CONSEQUENCES OF INTENSIVE BIOMASS HARVESTING IN BOREAL FOREST ENVIRONMENT Eero Kubin Finnish Forest Research Institute, Muhos HydroPredict’ 2010 Conference 20 - 23 September 2010 Prague, Czech Republic Layout Tuula Aspegren Metsäntutkimuslaitos Skogsforskningsinstitutet Finnish Forest Research Institute www.metla.fi
2 KEY WORDS • INTENSIVE BIOMASS HARVESTING • NITROGEN CYCLE • GROUNDWATER QUALITY • BOREAL FORESTS Layout Tuula Aspegren
3 Content 1. Background 2. Case Kivesvaara 3. Results 4. New challenges 5. Conclusions
4 1. Background • Forests in Finland • Round wood consumption since 1955 • Use of wood for energy and goal of use by 2020
5 The world’s forests 2000 http://www.fao.org/docrep/meeting/003/X9835e/X9835e3.gif Finland belongs mainly to the Boreal Forest Zone
6 http://www.metla.fi/metinfo/tilasto/julkaisut/vsk/2009/vsk09_08.pdf Roundwood consumption in Finland by category of use, 1955 – 2008 In 1955 – 1992, roundwood consumption for energy generation included also marginal quantities of industrial roundwood used in other consumption categories by e.g. small-sized dwellings, traffic and civil engineering. Sources: Finnish Forest Industries Federation; OSF: Finnish Forest Research Institute
7 The total use of forest chips 2000 – 2009 and the goal of use by 2020 Source: Metla, Forest Statistics Information Service 2010 use goal http://www.tapio.fi/files/tapio/Aineistopankki/Energiapuusuositukset_verkkoon.pdf
8 Structure of old spruce stand in northern Finland (66 o 22' N, 29 o 15' S) Biomass Based on the doctoral thesis by Eero Kubin 1984 % of total % kg/ha 5,5 TREE LAYER NEEDLES 6 600 14,2 LIVING BRANCHES 17 100 0,2 BRANCH SYSTEM CONES 200 3,4 DEAD BRANCHES 4 100 0,7 EPIPHYTES TOTAL BIOMASS 900 47,0 TRUNK WOOD 56 600 8,9 BARK 10 700 0,1 BUSHES TOTAL BIOMASS 100 20,0 ROOT SYSTEM TOTAL BIOMASS 23 800 76 120 100 100,0% GROUND-LAYER VEGETATION 16,3 3 000 DWARF SHRUBS TOTAL BIOMASS 0,5 100 HERBS AND GRASSES TOTAL BIOMASS 13,0 2 400 MOSSES TOTAL BIOMASS 66,9 12 300 ROOT SYSTEMS DWARF SHRUBS 3,3 12 600 HERBS AND GRASSES 100,0% 18 400 LITTER AND RAW HUMUS LITTER TOTAL AMOUNT 4 900 27,0 12 RAW HUMUS TOTAL AMOUNT 13 500 73,0 18 400 100,0% 100 All organic layers 156 900 Source: Havas, P. & Kubin, E. 1983. Structure, growth and organic matter content in the vegetation cover of an old spruce forest in Northern Finland. Ann. Bot. Fennici 20(2): 115-149.
9 Harvesting forest biomass is strongly increasing There are, however, open questions about the environmental effects, e.g. carbon flow, nutrients leaching to the groundwater and how to save site fertility
10 Perspective: Forest biomass harvesting in boreal forests needs more environmental research
11 11 2. Case Kivesvaara Kivesvaara research site is located in the middle of boreal forest zone in Finland Long-term ecological research since 1974 Extended 2007 to include the stump harvesting
12 Case Kivesvaara: Groundwater research in Hautala and Pahalouhi experimental sites Site preparation, soil and air temperature, nutrient leaching to surface water. Founded 1972 - 74 Site preparation. Nutrient leaching into the groundwater. Founded 1978 - 1985 Cleaning the sapling stand. Founded 1984 Mounding, different tree species, nutrient leaching to surface water. Founded 1986 Direct seeding with different soil treatment methods 2002 64 o 28'N, Prescribed burning 2002 27 o 33’E Lysimeters 2004 - Stump removal 2007 -
13 13 3. Results
14 The results are based on over 5 000 samples, from each over 10 elements were analyzed since 1985
15 Leaching of nitrate nitrogen into groundwater: Hautala 1985 - 2009 800 Waste wood left NO - N µg/l 3 Clearcutting, waste not collected Cleacutting, waste wood left 700 Uncut control Uncut control 600 Cleacutting 1986 500 Waste wood left Clearcutting June 20, 1986 400 300 200 100 0 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 200 3 2004 2005 2006 2007 2008 2009 Year 800 NO - N µg/l Waste wood harvested 3 Clearcutting, waste collected Cleacutting, waste wood harvested 700 Uncut control Uncut control 600 500 Clearcutting June 20, 1986 400 300 200 100 0 Cleacutting 1986 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Waste wood harvested Year
16 Leaching of nitrate nitrogen into groundwater: Pahalouhi 1985 - 2006 Waste wood left Cleacutting, waste wood left Uncut control Cleacutting 1986 Waste wood left Waste wood harvested Cleacutting, waste wood harvested Uncut control Cleacutting 1986 Waste wood harvested
17 Natural regeneration was also included 2002 No felling Seed tree cutting, pine Groundwater well Spruce shelterwood
18 Leaching after natural regeneration is less compared with clearcutting NO 3 -N µg/l
19 19 4. New challenges and research
20 New research on stump harvesting in Metla (Finnish Forest Research Institute) Financed also by the Ministry of Agriculture and Forestry
21 Project title: Ecological and silvicultural impacts of stump removal and harvesting of logging residues
Researh group Reseach Project leader Eero Kubin, groundwater Professor, Dr Anne Tolvanen, plant succession Professor, Dr Hannu Ilvesniemi, carbon flow Senior scientist, Dr Eila Tillman-Sutela, seed and restocking Researcher, Dr Oili Tarvainen, mycorrhiza Senior scientist Dr Juha Piispanen, chemical analyses Assistant researher, MSc (For.) student, Tanja Murto, carbon flow, restocking Other staff Metsätalousinsinööri Jorma Pasanen Suunnittelija Ari Kokko Tutkimusavustaja Reijo Seppänen Muhoksen toimipaikan laboratoriohenkilökuntaa 22.10.2010 22
23 Project layout Uncut forest Clearcutting Clearcutting + scalp mounding + spruce planting Block III Clearcutting + scalp mounding + collected 70 % of logging residure + spruce planting Clearcutting + scalp mounding + collected 70 % of logging residure + stump removal, left 25 stump/ha + spruce planting Clearcutting + scalp mounding + collected 100 % of logging residure + Block I stump removal, 100 % + spruce planting
24 Project objective New iformation for forestry practice and policy makers
25 Actions in Längelmäki stump harvesting study areas Uncut forest Clear cutting Stump removal Harvesting of logging residue
26 Preliminary results: nitrate in groundwater after stump harvesting Northern boreal zone Southern boreal zone NO 3 -N µg/l NO 3 -N µg/l 2007 2008 2009
27 27 5. Conclusions
28 NO 3 -N cycle in the boreal forest. What are the effects of climate change and whole tree harvest with lifting stumps? Natural state Conventional cutting Whole tree harvesting N-cycle N-cycle N-cycle Deposition: Interception + + Leaching: Depends on site + + (?) Decomposition: Slow + + (?)
29 Conclusions • Nitrogen leaching is increasing after cutting and harvesting. Maximum, however, in Kivesvaara study site is about 1 mg/l. EU limit value 50 mg/l. • Re-vegetation and stocking have important role to minimize nitrogen leaching • New technology has been developed for harvesting the stumps, but the environmental effects are still unknown • Nitrogen cycle in changing environment and intensive biomass harvesting needs more research, especially long term monitoring
Groundwater monitoring in Hautala, Finland NO 3 - N µg/l Short monitoring 3 years Uncut Waste control not collected Clearcutting: June 20, 1986 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Groundwater monitoring in Hautala, Finland NO 3 - N µg/l 5 years monitoring Uncut Waste control not collected Clearcutting: June 20, 1986 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Groundwater monitoring in Hautala, Finland NO 3 - N µg/l Long-term monitoring 1985 - 2009 Uncut Waste control not collected Clearcutting: June 20, 1986 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Photo Eero Kubin Photo Eero Kubin
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