| Objectives
The aim of the project is to quantify the relationship between environmental settings, fire severity and ecological effects of fires in oak dominated ecosystems. Specifically, EkBrand will test hypothesis proposing that fire supports oak dominance through its effects on soil organic layer and relative mortality rates of canopy trees. EkBrand has three main objectives:
(1) to parameterize the relationship between weather variability, fuel loads, fire intensity and severity,
(2) to parameterize the relationship between fire severity and oak regeneration,
(3) to evaluate effect on browsing of oak on the burned sites.
This knowledge should allow us to develop protocols of prescribed burns targeting a variety of outcomes (e.g. providing a range of mortality levels of canopy trees). In particular, we will establish fire severity levels, which favor oak survival, its regeneration and increased mortality of competing species.
The project relies on ongoing cooperation between SLU and unique possibilities to study large prescribed fires, which will be carried out within the framework of LifeTaiga project. LifeTaiga is an ongoing project within EU Programme for Environment and Climate Action, uniting Nature Protection agencies of the Swedish County Administrations. The project will conduct prescribed burns on ~3500 ha of protected forests in Sweden, of which a portion will be located oak-dominated forests of Southern Sweden.
Methods
EkBrand will use combination of pre- and post-fire field inventories, relying on ignition experiments and large (5-15 ha) prescribed fires (done in cooperation with LifeTaiga project) as the primary research tools. We will use on air-borne Lidar to make inventories of forest conditions, and generalized additive models to conduct the analyses.
Preliminary results
Our preliminary results suggest that oak has benefited from the surface fires in the past, relying for survival of large trees and post-fire recruitment, in part – through resprouting. Our dendrochronological reconstructions from the network of oak sites across Southern Sweden indicate that oak regeneration waves often followed low-severity surface fires.
Relevance to the Foundation's vision and Swedish nature conservation
Oak-dominated forests provide a range of ecosystem services, including maintenance of biodiversity and forest resilience in face of climate change. Across southern Sweden, expansion of spruce monocultures and decline in open habitats supporting oak regeneration has led to a decline in oak abundance. This trend calls for development of management programs to support preservation of oak-dominated forest ecosystems. Previous research suggests that fire disturbance has been an important factor maintaining oak regeneration in central and northern Europe. However, there is currently no data-supported guidelines on the application of prescribed fire to support its use as a management tool during conservation programs. The project will contribute to development of management strategies to maintain both the oak and biological diversity associated with this species in the Southern Swedish landscape.
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