Friedrich-Karl HoltmeierUniversity of Münster | WWU · Institute of Landscape Ecology (ILÖK)
Friedrich-Karl Holtmeier
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Publications (121)
Elevational and polar treelines have been studied for more than two centuries. The aim of the present article is to highlight in retrospect the scope of treeline research, scientific approaches and hypotheses on treeline causation, its spatial structures and temporal change. Systematic treeline research dates back to the end of the 19th century. Th...
Conifer mountain forests influence numerous human populations by providing a host of critical economic, sociological, and ecosystem services. Although the causes of the elevational, transitional boundaries of these forests (i.e., upper and lower timberlines) have been questioned for over a century, these investigations have focused predominately on...
No treeline-specific soil types exist. The treeline ecotone is usually characterized by a mosaic of soil types closely related to the locally varying conditions. Microtopography and the patchiness of the plant cover play an important role in this respect. Most soils in the treeline are shallow, and rich in skeletal material. Freeze-thaw processes a...
The article examines interactions between closely spaced clonal tree groups (spruce, fir, mountain birch) and dense tree clusters and their environment with special regard to Northern Europe, the Alps, and the Rocky Mountains. Modification of wind velocity and direction, trapping blowing snow and eolian dust, ground-shading and the release of sensi...
Transition zones between mountain forests and treeless tundra, i.e. treeline ecotones, are characterized by great regional variety. In this paper, we discuss the biodiversity in various trophic levels in treeline ecotones throughout Europe, with particular focus on recent changes in land use and climate in northern and central mountains. In norther...
Key message Layering plays a major role in treeline stability. Growth ring pattern of clonal groups reflects both an individualistic and an only temporally common response to the harsh treeline environment.
Abstract Clonal groups are common to alpine and polar treelines. Distribution, shape, architecture, and development of clonal Picea engelmanni...
Scales in treeline research depend on the objectives and must match the underlying natural processes. Factors and processes at one scale may not be as important at another scale. In the global view, the number of factors influencing climatic treeline position can be reduced to the effects of heat deficiency. Emphasis, however, should be laid on dif...
Treeline ecotones in mountains all over the world are dynamic and in many cases changing due to human impact, but there is considerable regional variation. Nevertheless, pressures on the treeline ecotone can be differentiated in abiotic (e.g. wind, fire, drought, avalanche), biotic (e.g. insects, browsing, pathogens) and anthropogenic ones (e.g. po...
Carl Troll published numerous articles in various fields of geography. The present article is focused on some remarkable publications that have essentially contributed to progress in physical geography. Articles on the relationships between vegetation and climates at the global and at the regional and local scales in a threedimensional view play a...
The functional role of keystone species is considered by way of examples. The focus is on termites, beavers, and kangaroo rats.
While many animal species are acting as ‘ecosystem engineers’, the term ‘keystone species’ in its proper sense should be restricted to cases where ecosystem stability, structure, function and dynamics are determined by onl...
There still are great uncertainties in the prediction of future climate. It also is uncertain whether the interrelationships of the many biological and physical factors and their relative intensity will be the same in a warmer climate. Changes of temperatures, precipitation regimes and increasing CO2 are discussed by way of examples, with the focus...
Examples of different habitats from different regions are the focus, including tropical savannas, temperate grasslands and woodlands, boreal and subarctic forests, and Arctic tundra.
Introductions of alien animal species and re-introductions of formerly native species to their original habitats are considered. Selected examples from different regions, including Subantarctic islands, Australia, New Zealand, North America, and Europe.
In its first English-language edition, this book introduces the many-faceted interactions of animal populations with their habitats. From soil fauna, ants and termites to small and large herbivores, burrowing mammals and birds, the author presents a comprehensive analysis of animals and ecosystems that is as broad and varied as all nature. Chapter...
The many-facetted, often controversial objectives and the resultant problem of landscape management and nature conservation are addressed, with special consideration of natural and tolerable habitat carrying capacity. The use of domestic ungulates as tools in landscape management and nature conservation is discussed and the role of public attitude...
The chapter deals with the interactions of animal populations and their habitats in a more general view. The many factors controlling these interactions are considered in the following sections.
Over the last century the global mean surface temperature has increased by about 0.6 °C and was most pronounced at high elevation and high latitude. Because the elevations and latitudes of treelines are strongly correlated with the occurrence of heat deficiency, climate warming is expected to generate denser forests below the treeline, as well as t...
Local landforms and microtopography control site conditions, spatial patterns, and dynamics in treeline landscapes. Several topography-related treeline types are presented and their responses to a warming climate discussed. On rugged mountain terrain, pronounced changes in vertical range and variety of treeline landscapes will not take place as lon...
Wild herbivorous mammals may damage treeline vegetation an cause soil erosion at a local scale. In many high mountain areas of Europe and North America, large numbers of red deer have become a threat to the maintenance of high-elevation forests and attempts to restore the climatic treeline. In northern Fennoscandia, overgrazing by reindeer in combi...
What causes the world-wide elevations of alpine treelines has intrigued
plant ecologists for over a century. Yet, the adaptive mechanisms and
corresponding environmental drivers that limit the occurrence of trees
to a maximum elevation are still being debated today. The most direct
evidence for current treeline movement is the occurrence of
seedlin...
The present study aims to contribute to a fine regional differentiation of Scots pine (Pinus sylvestris) response to climate change at its altitudinal margins in subarctic Finland north of 69 ° N (Utsjoki) and to find out whether a prompt establishment of new pines in response to climate change can be expected above the old pine tree limit in and a...
For over 100 years, mountain treelines have been the subject of varied research endeavors and remain a strong area of investigation. The purpose of this paper is to examine aspects of the epistemology of mountain treeline research-that is, to investigate how knowledge on treelines has been acquired and the changes in knowledge acquisition over time...
The altitudinal treeline ecotone is a windy environment where wind velocities and directions are controlled by local mountain topography and also by the distribution pattern and structures of tree stands. Wind may override the role of heat deficiency in determining treeline position, spatial pattern, ecological conditions, and tree growth. Regular...
This paper provides an overview on the main treeline-controlling factors and on the regional variety as well as on heterogeneity and response to changing environmental conditions of both altitudinal and northern treelines. From a global viewpoint, treeline position can be attributed to heat deficiency. At smaller scales however, treeline position,...
Mountain Timberlines is published as part of the broad area of research on the changing global climate and its impact on the environment. The upper timberline is the most conspicuous vegetation limit in high-mountain areas of all continents and islands, except for the Antarctic. The dynamics of timberline establishment and maintenance is being affe...
Surprising news from Finnish Lapland: landscape ecologists have been investigating northern European birch forests for 30 years. Tree lines respond to the continuous environmental changes slower than anticipated
The treeline ecotone in northern Finnish Lapland is characterized by a mosaic of sites with highly varying environmental conditions. Density, age structure, growth, and root systems of mountain birch seedlings (Betula pubescens ssp. czerepanovii [Orlova] Hamet-Ahti) were Studied in different microsite classes (deflation, lichen heath, dwarf shrub h...
The general trend of climatically-driven treeline advance is modified by regional, local and temporal variations. Treelines will not advance in a closed front parallel to the shift of any isotherm to higher elevations and more northern latitudes. The effects of varying topography on site conditions and the after-effects of historical disturbances b...
The objective of this paper is to differentiate the landscape in the treeline ecotone in Subarctic Finland with an examination of its mosaic structure and functional role in treeline dynamics. Highly varying topography is a key factor controlling drainage conditions, vegetation, local climates and soils. Natural drainage
classes, soil data (pH, Cor...
Seven peat and 40 dead wood remains (mountain birch) were sampled within and above the present treeline ecotone on two mountains (Rodjanoaivi, Koahppeloaivi/Staloskaidi) along the Tenojoki in northernmost Finnish Lapland. The oldest peat samples (‘summit peats’) date back to about 2000 yr BP. They accumulated during cool and increasingly humid clim...
The pedogenesis and interactions among soil, vegetation, and snow cover of four alpine snowbeds on silicate rocks in the Upper Engadine (Central Alps, Switzerland) were investigated. The long-lasting snow cover of snowbeds causes differences in pedogenesis and soil properties compared to adjacent alpine sward. Because of the drainage characteristic...
The sensitivity and response of northern hemisphere altitudinal and polar treelines to environmental change are increasingly discussed in terms of climate change, often forgetting that climate is only one aspect of environmental variation. As treeline heterogeneity increases from global to regional and smaller scales, assessment of treeline sensiti...
In the treeline ecoton, fragmentary tree stands, interspersed with open patches of subalpine and alpine vegetation, strongly influence the relocation of blowing snow. The extent and manner of this relocation is determined by size, coverage, structure and morphological characteristics of the fragmentary stands. Once relocated, the snow deposits may...
Change in the timberline ecotone is described by comparing field notes and observations in study areas in northern Utsjoki and Pallastunturi from 30 years ago to the present situation. Most of the young growth of pine and spruce that had invaded the forest-tundra ecotone and even advanced beyond the former treeline during the favorable period betwe...
The objective of our research was to find out if forest will invade the treeless areas in the present treeline ecotone in northern Finnish Lapland and which factors might impede forest advance. The field studies were carried out on Ailakkavaara near Kilpisjärvi, in the Pallastunturi area, and in northern Utsjoki
(Rodjanoaivi, Koahppeloaivi-Stalosk...
Advances in Global Change Research 14, pp. 369
The upper timberline is the most conspicuous vegetation limit in high-mountain areas of all continents, except for the Antarctic. Timberline is also an important ecological boundary, marked by a change in site conditions and plant communities when crossing the forest limit. For example, above the closed forest topoclimatic conditions, soil distribu...
A mosaic of tree clumps, scattered groves, isolated, more or less deformed tree individuals and treeless patches covered by low shrubs, herbs, and grasses characterizes the timberline ecotone. It depends on the geographical position of a mountain range whether the treeless communities consist mainly of dwarf shrubs and grasses (e. g., European Alps...
The previous chapters have provided a first insight into the heterogeneity, complexity and great physiognomic and ecological variety of the “timberline phenomenon”; a heterogeneity and variety that largely have faded out when scientists mainly focused on the one factor (mainly temperature) controlling the altitudinal position of timberline and on t...
Undoubtedly, more attempts have been made to define timberline than other vegetation limits, in particular for correlating the location of this prominent vegetation- and landscape-limit to certain isotherms or other altitudinal limits, such as snow line, for example (e. g., Hermes, 1955). Most definitions refer to a certain minimum tree height or m...
This book is motivated by studies of global climate change and its impact on the environment, a topic which is increasingly being discussed among scientists as well as by the general public. One major point of concern is the possible shift of vegetation zones to higher altitudes and greater latitudes. In particular, attention is being given to nort...
Investigations on Spatial Heterogeneity of Humus Forms and Natural Regeneration of Larch (Larix decidua Mill.) and Swiss Stone Pine (Pinus cembra L.) in an Alpine Timberline Ecotone (Upper Engadine, Central Alps, Switzerland). The north-west facing study area in the Upper Engadine (Central Alps, Switzerland) encompasses the whole timberline ecotone...
In the forest-alpine ecotone at Stillberg (Dischmatal/Switzerland) the morphology of humus forms and the spatial variability of organic layer properties were investigated. At northeast-exposed gully sites mulls with high acidity in the A-horizon occur. They were classified after the Canadian classification of humus forms as Rhizomulls. Mors occur o...
In the forest-alpine ecotone at Stillberg (Dischmatal/Switzerland) the morphology of humus forms and the spatial variability of organic layer properties were investigated. At northeast-exposed gully sites mulls with high acidity in the A-horizon occur. They were classified after the Canadian classification of humus forms as Rhizomulls. Mors occur o...
Arbeiten aus dem Institut für Landschaftsökologie 8, pp. 337
Arbeiten aus dem Institut für Landschaftsökologie 6, pp.348
Tree islands that originate from layering are typical of the forest-alpine tundra ecotone on Niwot Ridge and other similar wind-exposed ranges in the Rocky Mountains. Dying off at their windward front and elongating by layering at their leeward end, the tree islands slowly move downwind. They strongly influence site conditions (snow cover pattern,...
Two North American bird-dispersed pines, Pinus albicaulis and Pinus flexilis, were previously found to occur in three growth forms: single-trunk, single genet multi-trunk, and multi-genet tree cluster. The latter two forms are morphologically similar and distinguishable only by genetic analysis; they are together referred to as ''tree clumps.'' In...
Wind-mediated seed dispersal is very irregular, and it depends on chance whether the windborne seeds will reach a suitable seed bed. Nutcrackers Nucifraga spp. cache seeds (of Pinus cembra and related species) at sites where the winter snow cover disappears relatively early. Some tree species at timberline, such as spruces and firs, can reproduce a...
The extreme patchiness of plant communities and site conditions in the upper timberline ecotone is primarily controlled by the influence of microtopography and scattered tree islands on windflow near the soil surface, which in turn affects the distribution pattern of the winter snow cover. Snow accumulates inside the tree islands, and large snowdri...
Within the forest-tundra-ecotone of the Rocky Mountains ribbon-like structures, which can be attributed to the influence of the wind, can be observed locally. The forest strips run either perpendicular or parallel to the prevailing wind direction (west). These elongated tree-islands are called 'ribbons' and the intervening wet and treeless meadows...
The term "Krummholz" is applied to the bush-like growth-forms of Pinus mugo prostrata, Alnus viridis, and some other species which are genetically determined. The term has also long been used by English-speaking botanists to refer to the climatically stunted and distorted trees in the forest-tundra ecotone. Thus, distinct ecological and plant-geogr...
Projects
Projects (2)
The objective is to come to a a better understanding of the great variety and herogeneity of treeline at different scales.
Treeline ecosystems are important indicators of environmental change, because they are heavily impacted by environmental drivers, in particular changed climate and land use, resulting in land abandonment and reforestation of formerly treeless areas. With a focus on treeline ecosystems, this Action aims at integrating scientific methods and results related to the biodiversity conservation and sustainable use of natural resources under climate and land use change. The Action will investigate the drivers and extent of contemporary and future environmental changes in European mountain forests, developing methods for estimating their resilience and define consequences for society. This knowledge provides the scientific basis necessarily to develop and adjust management strategies together with local and regional stakeholders as well as policy recommendations for national and European policy makers. Applying the DPSIR (Drivers, Pressures, State, Impact, Response) framework, the joint actions of the SENSFOR network will contribute to the development of strategies for preserving ecosystem services and biodiversity conservation in sensitive mountain areas in Europe.