Wyniki wyszukiwania - BazTech

Ograniczanie wyników

1 Polish Journal of Ecology

1 2009

Znaleziono wyników: 1

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: sekwencja wieku

Sortuj według:

Ogranicz wyniki do:

Cheng D., Zhong Q., Wang G.

Polish Journal of Ecology

2009

Vol. 57, nr 3

441-449

Metabolic theory of ecology predicts a 3/4 power relationship between annual productivity P[T] and body size M[T] (i.e., P [is proportional to] M[^3/4]), which has important implications to estimates of carbon fluxes, ecosystem health, global carbon budgets, and a variety of other phenomena. To test this prediction, we examined a large dataset for Chinese forests. Such dataset covers six major forest biomes and a total of 17 forest types grown across a range of annual temperature (-6.6 to 25.2[degrees]C), mean annual rainfall (27 to 2989 mm), elevation (10 to 4240 m a.s.l.), and stand age (3 to 350 yrs.). Reduced major axis (RMA) regression analyses were used to compare the P[T] versus M[T] scaling exponents and normalization constants (i.e., slopes and Y-intercepts of log-log linear relationships, respectively). Comparisons were made for ten different age-sequences (stand age ranges from 20 to 200 yrs). When stand age was less than 100 yrs, relationship of P[T] versus M[T] had similar scaling exponents ([alpha][RMA]>> 1.0), while the Y-intercepts decreased systematically. When stand age exceeded 140 yrs, scaling exponents decreased ([alpha][RMA] <0.86). Both the aboveground annual productivity and aboveground body size per individual tree (P[A] and M[A], respectively) showed the same behavior. We therefore conclude that the relationship of P[T] versus M[T] systematically declined with the stand age, and was inconsistent with the predictions of metabolic theory.