TY - JOUR
T1 - Multi-aged micro-neighborhood patches challenge the forest cycle model in primeval European beech
AU - Zenner, Eric K.
AU - Peck, Jerilynn E.
AU - Trotsiuk, Volodymyr
N1 - Funding Information:
EZ conceived the approach; all authors developed the methodology; VT acquired data; EZ performed statistical analyses; JP and EZ wrote the first draft of the manuscript and all authors contributed to the final version. This work was supported by the USDA National Institute of Food and Agriculture Hatch Appropriations under Project #PEN04639 and Accession #1015105.
Publisher Copyright:
© SISEF.
PY - 2020/6
Y1 - 2020/6
N2 - As currently framed, the forest cycle model that underlies close-to-nature management in temperate beech forests throughout the globe specifies an or-derly sequence of temporal development within even-aged patches comprising the forest mosaic. Although this model has been widely applied to European beech (Fagus sylvatica L.) forests, the underlying assumptions of disturbance-induced even-agedness (i.e., within-patch age homogeneity) and competition-induced size differentiation (i.e., within-patch size heterogeneity) have not been tested in natural beech forests due to prohibitions on tree coring in primeval forest reserves. In a rare and unprecedented test dataset of spatially explicit tree ages in an old-growth European beech forest, we employed trian-gulated irregular networks of Delaunay triangles to objectively identify natural tree neighborhoods to determine if neighboring (i.e., within-patch) trees were even-or, at most, two-aged. Age differences among neighboring trees (summa-rized in 25-yr age classes) were rarely <25 yrs and mostly >50 yrs, while the few "even-aged" patches were very small (100 m2) and relatively young (<150 yrs). In this first assessment of the assumptions underlying the forest cycle model in European beech, we observed neither the even-aged cohorts ex-pected for disturbance-induced patches in different phases of development, nor the size differentiation among similarly aged trees that should arise from the neighborhood dynamics of competition, self-thinning, and growth. The lack of patches indicating demographic turnover is fundamentally inconsistent with the forest cycle model as it is currently framed. We call for further explo-ration of spatially-explicit tree age datasets to determine the generality of these observations.
AB - As currently framed, the forest cycle model that underlies close-to-nature management in temperate beech forests throughout the globe specifies an or-derly sequence of temporal development within even-aged patches comprising the forest mosaic. Although this model has been widely applied to European beech (Fagus sylvatica L.) forests, the underlying assumptions of disturbance-induced even-agedness (i.e., within-patch age homogeneity) and competition-induced size differentiation (i.e., within-patch size heterogeneity) have not been tested in natural beech forests due to prohibitions on tree coring in primeval forest reserves. In a rare and unprecedented test dataset of spatially explicit tree ages in an old-growth European beech forest, we employed trian-gulated irregular networks of Delaunay triangles to objectively identify natural tree neighborhoods to determine if neighboring (i.e., within-patch) trees were even-or, at most, two-aged. Age differences among neighboring trees (summa-rized in 25-yr age classes) were rarely <25 yrs and mostly >50 yrs, while the few "even-aged" patches were very small (100 m2) and relatively young (<150 yrs). In this first assessment of the assumptions underlying the forest cycle model in European beech, we observed neither the even-aged cohorts ex-pected for disturbance-induced patches in different phases of development, nor the size differentiation among similarly aged trees that should arise from the neighborhood dynamics of competition, self-thinning, and growth. The lack of patches indicating demographic turnover is fundamentally inconsistent with the forest cycle model as it is currently framed. We call for further explo-ration of spatially-explicit tree age datasets to determine the generality of these observations.
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U2 - 10.3832/ifor3309-013
DO - 10.3832/ifor3309-013
M3 - Article
AN - SCOPUS:85086323226
VL - 13
SP - 209
EP - 214
JO - IForest
JF - IForest
SN - 1971-7458
IS - 3
ER -