CLIMATIC CONDITIONS AND TROPICAL, MONTANE FOREST PRODUCTIVITY - THE FOG HAS NOT LIFTED YET

Citation
La. Bruijnzeel et Ej. Veneklaas, CLIMATIC CONDITIONS AND TROPICAL, MONTANE FOREST PRODUCTIVITY - THE FOG HAS NOT LIFTED YET, Ecology, 79(1), 1998, pp. 3-9
Citations number
71
Categorie Soggetti
Ecology
Journal title
ISSN journal
00129658
Volume
79
Issue
1
Year of publication
1998
Pages
3 - 9
Database
ISI
SICI code
0012-9658(1998)79:1<3:CCATMF>2.0.ZU;2-S
Abstract
Tropical montane cloud forests (TMCF) differ from lowland moist forest s in structure (low stature, small and tough leaves, low diversity) an d functioning (low productivity, low nutrient-cycling rates). To expla in these differences, a variety of hypotheses have been proposed, most of which are related directly or indirectly to climate, but none of t hese provides a satisfactory explanation for all typical TMCF traits. The single climatic factor shared by all TMCF, the frequent occurrence of low cloud, has multiple effects, but not all are well understood, In this paper we describe and analyze the climatic and soil-moisture c onditions prevailing in TMCF as reported in the literature. TMCF evapo transpiration is limited by both climatic conditions and canopy conduc tance. TMCF productivity is low, but our understanding of these forest 's carbon balance is incomplete. Leaf photosynthetic capacity is not p articularly low, but canopy photosynthesis probably is, due to persist ent cloudiness (low radiation) and a low leaf-area index (LAI). We sug gest that the low LAI of TMCF is controlled by light climate and by le af structure and longevity. TMCF productivity is probably further limi ted by a substantial investment of carbon in the growth and functionin g of a relatively large root system, which is itself a consequence of unfavorable soil conditions.