Leader: Jānis Donis
Start date: 15.03.2022
End date: 15.11.2022

Study supported by the Forest Development Fund (agreement No. 22-00-S0MF10-000047)

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In order to ensure the preservation of structures important for biodiversity in Latvian forests, in 1997 the State Forest Service adopted instructions stipulating that separate (5 to 10 trees per ha) trees should be left in the final felling. The Forest Law (2000) and the regulations of the corresponding Cabinet of Ministers stipulate that at least 5 ecological trees (EC) per ha should be preserved. In the forests managed by JSC "Latvia's State Forests", 10 ecological trees per ha are preserved.In the protection plans for various species of birds, it is proposed to increase the number of ecological trees to 20–30 trees per ha. A comprehensive assessment of the impact of trees of the previous generation preserved in felling on forest ecosystem services has not been carried out in Latvia so far.

The aim of the study is to evaluate the conservation efficiency of the previous generation of trees and their impact on other forest ecosystem services as well.

Tasks of the study:

  1. To evaluate the survival of the trees of the previous generation preserved in felling and the factors affecting it:
    - detection of ecological trees in aerial images of various cycles of the LGIA (at least 800 felling/young stands);
    - survey of objects in nature to validate the accuracy of ecological tree detection (at least 40 felling/newly grown forest research stations in forests or forests of other owners);
    - ecological tree survival analysis based on aerial image time series analysis of LGIA and LGIA LiDAR data.
  2. To assess the impact of ecological trees of different spatial location on the growth of new generation trees in dry forests:
    - inventory data of the new generation of trees and their dynamics depending on the distance to ecological trees or their groups in forests (at least 40 young stands);
    - analysis of field data obtained by the task.
  3. Assessment of the functional role of ecological trees:
    - assess the occurrence of tree-related micro-habitats on ecological trees in at least 20 young plants;
    - evaluate the diversity of epiphytes and epixillites in 20 young plants;
    - the role of ecological trees in the provision of other forest ecosystem services.