Disturbance assessment at long- term forest experiments: an Estonian case

Transcription

1 Disturbance assessment at long- term forest experiments: an Estonian case Ahto Kangur,, Allan Sims,, Henn Korjus, Andres Kiviste SNS Growth and Yield Researchers Meeting 09.. June 2009 Kokkola, Finland

2 Outline Old long-term forest experiments in Estonia Long-term experiments with irregular measurement intervals: a Järvselja case Tracking changes in long-term measurement series Complementary data for long-term forest growth and yield study plots time series

3 Long-term forest experiments in Estonia Experiment Establisher and/or current manager Series description series 1 Andres Mathiesen Järvselja puistu kasvukäigu katsealad 2 Lembit Muiste Järvselja hooldusraiete katsealad 3 Heino Seemen Väetamiskatsed 4 Elmar Kaar Karjääride taasmetsastamise katsed 5 Andres Kiviste Sagadi erineva algtiheduse katse 6 Metsahoiu SA Looduslikkuse taastamise katsealad 7 Aivo Vares, Arvo Tullus Hübriidhaava katsealad 8 Kalev Jõgiste Järvselja loodusliku uuenduse katseala 9 Aivo Vares, Merit Kund Lehtpuude projekt 10 Metsakaitse- ja metsauuenduskeskus Endise Metsakorralduskeksuse püsivaatlusalad 11 Heino Kasesalu Järvselja võõrpuuliikide katsealad 12 Malle Kurm Metsaselekstiooni katsealad 13 Raul Pihu Metsaselektsionikatsealad 14 Marek Metslaid Järvselja hariliku kuuse eeluuenduse katsealad 15 Heino Kasesalu Järvselja Oak experiments 16 Märt Hanso, Rein Drenkhan Hariliku männi geograafilise päritolu katseala Old : 172 experimental areas 1722 plots In total: 238 experimental areas 2162 plots

4 Long-term experiments with irregular measurement intervals Why it is even an issue? Scientific value and usability of previously abandoned field plots Is it worthwhile to continue with the measurements after long period of abandonment? How to estimate the missing data for the period of observational gap?

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6 Basic data about Järvselja Järvselja Training and Experimental Forest Established in 1921 by Tartu University Land area ha, forest land 6040 ha Four tree species dominate: birch (47,3%), pine (20,7%) spruce (11,9) and black alder(6,3%)

7 Inconsistencies and uncertainties in measuring and data recording 1. Changes in experimental design and measurement prescription. Changing policies, new challenges Financing, including funding termination Experiment management and leadership changes 2. High variability in measuring staff and assessment techniques Staff calibration Advances in technology and understanding 3. Changes in data recording and storing.

8 First task in Reviving

9 The measurement series data Measurement series Plots Revived Trees Establishment Number Measurements Number Measurements MAT MUI KIV SAT Total

10 Distribution of revived sample plots by site type and main species Group of types Pine Spruce Birch Other Total Fully drained swamp forests Meso-eutrophic forests Mesotrophic forests Nemoral forests Bog moss forests 5 5 Total

11 Recognizing disturbances in time series 1. Changes we have been looking Natural disturbnces Anthropogenic effect Example is given with pine dominated stand.

12 Recognizing disturbances in time series For each measurement was calculated: = t i = cnx t Nx 1 i cnx t - accumulated number of trees died (x=dead) and cut (x=cut), t measurement intervall (years) The weight of a disturbance NG rn rg N thn tot = = rn is the ratio between removed (N thn ) G thn / N / G tot and total (N tot ) stem number, rg ratio between removed (G thn ) and total basal area (G tot )

13 Detiles about disturbnces in time series at plot M046_11_01 Year Area Number of trees per ha Basal area m2 per ha Cumul. trees per ha live cut dead live cut dead rg NG unknown cut dead

14 Detiles about disturbnces in time series at plot M046_11_01

15 Reconstruction of height and diameter chronology Annual height growth is measured as a distance between whorls, what is detected by branch knots on the split stem surface. Problems!?

16 Matching permanent plot re-measurements with height growth reconstruction data Plot No: M046 Height increment (cm) tree1 thinning no of trees dead trees Year

17 Thank you! Forest Modelling Information System Järvselja Training and Experimental Forestry Centre