© 2005 Heron Publishing—Victoria, Canada
Growth of advance regeneration of Norway spruce after clear-cutting
Marek Metslaid (1, 2), Triin Ilisson (3), Marta Vicente (4), Eero Nikinmaa (5) and Kalev Jõgiste (1)
1. Forest Research Institute, Estonian Agricultural University, Kreutzwaldi 5, 51014, Tartu, Estonia / 2. Corresponding author (mmarek@eau.ee) / 3. Faculty of Forestry, Estonian Agricultural University, Kreutzwaldi 5, 51014, Tartu, Estonia / 4. Department of Agronomy and Forestry, Lleida University, Alcalde Rovira Roure, 177, 25198 Lleida, Catalonia, Spain / 5. Department of Forest Ecology, University of Helsinki, P.O. Box 24, 00014, University of Helsinki, Finland / Received January 4, 2005; accepted March 11, 2005; published online May 2, 2005
Summary
We developed a basal area growth model for recovery of advance growth of Norway spruce trees after clear-cutting. Stem diameter
growth at ground level and needle-mass characteristics were measured on permanent sample plots in Estonia. Both tree ring
analysis (destructive sampling on one sample plot) and yearly repeated measurement data (two plots) were used to quantify
advance growth. Basal area growth of small trees was estimated by multiple regression analysis. Previous-year basal area of
the tree and basal area growth explained tree performance the next year. Tree needle-mass variables characterizing the acclimation
status of the tree were included in the model as explanatory factors. Needle samples (one shoot from the upper third of each
tree crown) were collected each year after the growth period from all sample trees. Needle masses of shoots from consecutive
years were correlated and this variable was used as a predictor in the simulation model. Accelerating growth was observed
in trees that exceeded the growth threshold in the year after release: the greater the needle mass per shoot, the greater
the acceleration in growth. Competition among advance regeneration trees was included in the model: small trees under taller
neighbors exhibited reduced growth. We found that trees released from a long period of heavy shade can survive, but the time
needed for acclimation and resumption of competitive growth rates is considerably longer than for trees released from light
shade. Such trees can be used for forest regeneration, but competition control (particularly reducing the proportion of fast-growing
hardwoods) is required.
Keywords:
acclimation, growth, sapling, shade tolerance.
