Temperature parameters of humid to mesic forests of eastern Asia and relation to forests of other regions of the Northern Hemisphere and Australasia

Abstract

Compilation of temperature data from more than 400 stations in the humid to mesic forests of Asia indicates that the boundaries of physiognomic units of vegetation approximately coincide with cer tain major temperature parameters. Most boundaries between broad-leaved forests coincide with mean annual temperature values; a mean temperature of the cold month of 1°C delineates dominantly broad-leaved deciduous forests from broad-leaved evergreen forests. Forests in which conifers are either dominant or a major emergent element typically are separated from broad-leaved forests by sum mer heat. Based on the approximate coincidence of certain mean annual temperature values with vegetational boundaries, a sixfold division of forest climates is proposed: tropical (more than 25°C), paratropical (20-25°C), subtropical (13-20°C), temperate (10-13°C), paratemperate (3-10°C), and subtemperate (less than 3°C).Examination of latitudinal and altitudinal zonation of vegetation indicates that the concept of a given vegetational belt descending to lower altitudes in a poleward direction is at best a gross generaliza tion and is in some respects invalid. Mesic broad-leaved deciduous forests do not live in areas in which the mean annual range of tem perature is less than 19-20°C; hence such vegetation cannot be rep resented on tropical mountains. Mesic regions of Australasia have a low mean annual range and therefore have no broad-leaved decidu ous forests.Comparison of the climatic data from Asia with data from other areas of the Northern Hemisphere indicates: (1) A large area of east ern North America that might be expected to have broad-leaved evergreen forests has a broad-leaved deciduous forest similar to the secondary vegetation of some broad-leaved evergreen forest regions of Asia, probably as a result of geologically abnormal cold waves. (2) The "Mixed Mesophytic forest" of eastern United States is largely not the temperature analog of the Mixed Mesophytic forest of eastern Asia. (3) A large area of western Europe that might be expected to have a coniferous forest has a broad-leaved deciduous forest, prob ably as a result of historical factors associated with repeated glaciation. (4) Western United States has no temperature-vegetation anomalies based on the temperature parameters of eastern Asian vegetation. Comparison of the climatic data from western Europe and eastern North America indicate that the "nemoral" zones of the two areas are largely not temperature analogs.The vegetation of New Zealand, which has been problematic in forest classification, is largely the vegetation expected in such tem perature regimes. In certain given temperature parameters, mesic vegetation tends to be a microphyllous broad-leaved evergreen forest with an emergent stratum of conifers. Such forests can be observed in the Himalayas, as well as in New Zealand.

Fossil evidence for a herbaceous diversification of early eudicot angiosperms during the Early Cretaceous

“…Teeth of this type are sites of guttation; the loss of water at tooth apices prevents flooding of the leaf mesophyll under conditions of high soil moisture, high humidity and low evaporative demand [53][54][55]. Environments such as forest understory and riparian corridors in tropical and temperate climates typically host plants with hydathodal teeth [49,[56][57][58][59][60][61]; but hydathodal teeth also occur in some marginally or semi-aquatic ranunculalean herbs that grow under bright, subareal conditions [39].…”

Late Cretaceous and Paleocene terrestrial climates of New Zealand: Leaf fossil evidence from South Island assemblages

“…The two modern analogue methods applied in this study were the univariate approach LMA (Wolfe 1971(Wolfe ,1979Wing & Greenwood 1993) and the multivariate method CLAMP (Wolfe 1993(Wolfe , 1994. LMA is based on correlations seen in some modern vegetation between the percentage of dicotyledonous leaf forms that have entire (not serrated) margins and mean annual temperature.…”

“…2002), Greymouth (Kennedy & Raine 2001), and North Otago (Fig. 1), and they have been analysed using univariate (LMA) (Wolfe 1971(Wolfe , 1979Wing & Greenwood 1993) and multivariate (CLAMP) (Wolfe 1993) methods to estimate climate variables.…”

Refining CLAMP — Investigations towards improving the Climate Leaf Analysis Multivariate Program

“…Methodologically, CLAMP is a development of Leaf Margin Analysis (LMA). LMA is a method based on the observations of Sinnott (1915, 1916), which were subsequently expanded by others (e.g., Wolfe 1971Wolfe , 1978Wolfe , 1979. Unlike the univariate LMA that yields only a single climate variable (mean annual temperature), CLAMP is based on a multivariate statistical technique for determining, quantitatively, a range of palaeoclimate parameters utilizing the physiognomic characteristics of the fossilised leaves of woody dicots.…”