4. Methods
4.1. Tree Biomass and Production
A detailed description of the methods developed and applied to the tree layer and the results obtained are provided
in Andersson (1970c) and Nihlgård (1972). Therefore, only a summary is given here. The estimates of tree
biomass and production were based on allometric regressions, using the relationship between destructive and
non-destructive measurements. The estimation procedure comprised four basic steps:
• Stand analyses of non-destructive measurements—tree height and diameter.
• Destructive measurements of sample trees: stem sections or discs, branches, twigs and roots—diameter, age.
• Application of the stand data to the regressions of the sample trees obtained in (2).
• Additional observations on e.g. litterfall.
The above-ground biomass and production of trees were studied specifically for 11 Quercus robur, 6 Tilia
and Sorbus and 18 Corylus. Studies of the below-ground parts with roots were limited to three individuals of
each tree species. The main root biomass fraction, comprising roots > 0.5 cm in diameter, was collected around
the tree. The fine root biomass (
4. Methods4.1. Tree Biomass and ProductionA detailed description of the methods developed and applied to the tree layer and the results obtained are providedin Andersson (1970c) and Nihlgård (1972). Therefore, only a summary is given here. The estimates of treebiomass and production were based on allometric regressions, using the relationship between destructive andnon-destructive measurements. The estimation procedure comprised four basic steps:• Stand analyses of non-destructive measurements—tree height and diameter.• Destructive measurements of sample trees: stem sections or discs, branches, twigs and roots—diameter, age.• Application of the stand data to the regressions of the sample trees obtained in (2).• Additional observations on e.g. litterfall.The above-ground biomass and production of trees were studied specifically for 11 Quercus robur, 6 Tiliaand Sorbus and 18 Corylus. Studies of the below-ground parts with roots were limited to three individuals ofeach tree species. The main root biomass fraction, comprising roots > 0.5 cm in diameter, was collected aroundthe tree. The fine root biomass (<0.5 cm diameter) was collected in 10 pits measuring 50 cm × 50 cm × 60 cmexcavated along a transect at regular intervals of 2 m.
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