LONG TERM CONSEQUENCES OF INTENSIVE BIOMASS HARVESTING IN BOREAL FOREST ENVIRONMENT Eero Kubin Finnish Forest Research Institute, Muhos Layout Tuula Aspegren Metsäntutkimuslaitos Skogsforskningsinstitutet Finnish Forest Research Institute www.metla.fi HydroPredict 2010 Conference 20-23 September 2010 Prague, Czech Republic
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) Based on the doctoral thesis by Eero Kubin 1984 Biomass kg/ha % % of total TREE LAYER NEEDLES LIVING BRANCHES 6 600 17 100 5,5 14,2 BRANCH SYSTEM CONES DEAD BRANCHES 200 4 100 0,2 3,4 EPIPHYTES TRUNK TOTAL BIOMASS WOOD 900 56 600 0,7 47,0 BUSHES BARK TOTAL BIOMASS 10 700 100 8,9 0,1 ROOT SYSTEM TOTAL BIOMASS 23 800 120 100 20,0 100,0% 76 GROUND-LAYER VEGETATION DWARF SHRUBS HERBS AND GRASSES MOSSES ROOT SYSTEMS LITTER AND RAW HUMUS TOTAL BIOMASS TOTAL BIOMASS TOTAL BIOMASS DWARF SHRUBS HERBS AND GRASSES 3 000 100 2 400 12 300 600 18 400 16,3 0,5 13,0 66,9 3,3 100,0% 12 LITTER RAW HUMUS TOTAL AMOUNT TOTAL AMOUNT 4 900 13 500 27,0 73,0 12 18 400 100,0% All organic layers 156 900 100 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 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 Prescribed burning 2002 Lysimeters 2004-64 o 28'N, 27 o 33 E Stump removal 2007 -
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 Waste wood left 800 700 600 NO - N µg/l 3 Clearcutting, Cleacutting, waste wood not collected left Uncut Uncut control Cleacutting 1986 Waste wood left 500 400 Clearcutting June 20, 1986 300 200 100 0 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 Year Waste wood harvested 800 700 600 NO - N µg/l 3 Clearcutting, Cleacutting, waste wood collected harvested Uncut control 500 400 Clearcutting June 20, 1986 300 200 100 Cleacutting 1986 Waste wood harvested 0 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 20032004 2005 2006 2007 2008 2009 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 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 Clearcutting + scalp mounding + collected 70 % of logging residure + spruce planting Block III Clearcutting + scalp mounding + collected 70 % of logging residure + stump removal, left 25 stump/ha + spruce planting Clearcutting + scalp mounding + collected 100 % of logging residure + stump removal, 100 % + spruce planting Block I
24 Project objective New iformation for forestry practice and policy makers
25 Actions in Längelmäki stump harvesting study areas Uncut forest Clear cutting Harvesting of logging residue Stump removal
26 Preliminary results: nitrate in groundwater after stump harvesting Northern boreal zone NO 3 -N µg/l Southern boreal zone NO 3 -N µg/l 2007 2008 2009
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 control Waste 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 control Waste 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 control Waste 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