Low apoplastic water potentials can affect trees by decreasing the hydraulic conductivity of xylem due to embolism and by causing dehydration stress in living cells. Low apoplastic water potentials regularly occur in trees during summer and winter. These can either be caused by loss of water due to ...

Trees have different mechanisms to avoid and mitigate biotic and abiotic stresses, among which resin is essential for conifer trees. Conifer resin is also a large pool of monoterpenes that – similarly to other volatile organic compounds (VOCs) produced by plants, e.g. methanol, acetone and...

Tree vascular tissues connect resource availability to tree physiological processes and growth. The xylem transports water from the soil up to the canopy of even 100-metre tall trees, whereas phloem transport connects the photosynthesis in leaves and the tree metabolic processes, including growth...

This thesis investigates water and nitrogen resource use patterns of trees and grasses, and examines the effects of competition between trees and grasses on resource storage in perennial grasses. Furthermore, the functionality of trees in two common human land use types in African drylands is...

Tropical forests occur along a rainfall gradient where annual amount, the length and intensity of dry season vary and water availability shapes therefore strongly the distribution of tree species. Annual rainfall in West Africa has declined at a rate of 4% per decade, and climate change models...

Species of the Heterobasidion annosum sensu lato (s. l.) complex are causing root and butt rot of conifers. Mycoviruses are usually cryptic, but some of them may cause hypovirulence (reduced virulence) or mutualistic effects on their fungal hosts. We explored new Heterobasidion viruses, and...

This thesis aimed to study the interaction between Eucalyptus woodlot trees and crops in fields next to the woodlots in southern Rwanda. General allometric equations were developed relating tree diameter and height to total and component aboveground tree biomass in coppice and planted stands and...

In this thesis, I investigated the environmental changes that could have formed the basis for changes in tropical tree growth. I used two relatively new tools in tropical forest ecology: tree-ring measurements and stable isotope analyses. In this project, ∼1400 trees of 15 species were examined...

This research focuses on stand dynamics and ecological recovery in miombo woodlands, Morogoro, Tanzania. The study uses the Kitulangalo Permanent Sample Plots (PSPs) to analyse tree species' site-specific growth, regeneration dynamics, and stand development using empirical and modeling approaches....

This thesis unravels the evolutionary history and the historical biogeography of the family Ochnaceae, with special emphasis on the genus Campylospermum and its relationship with sister genera. Chapter 1 provides an introduction to the organisms studied and the general aims of the project. Chapter...