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  • 31 Reads
Project PROTECTFOREST©: Early detection of bark beetle infestation by drone-based monoterpene detection

Early detection of bark beetle infestation is a costly and time consuming task, as it can only be done reliable by personal screening the crowns for resin flow. Drone based detection systems prooved to be able to detect bark beetle infestation in the "red crown" stage. This is insufficient for a fast response under increasing infestation rates, as either the work load is very high or the tree is detected after the beetles have already multiplied and infested other trees. Therefore, a fast response method is needed to detect infested trees in the "green" stage. In this stage, only the hardly visible optical impression of the resin flow and the resin odor are detection cues.

A semi-conductor gas sensor containing three gas sensor elements was designed and integrated on a drone platform to detect monoterpene emissions over the crowns of a mixed deciduous/conifer forest. The sensor system was calibrated in the lab and tested under artificial lab and field conditions. The detection of alpha Pinen, the predominant mono terpene emitted by conifer resin, prooved to be successful. The detection of infested trees was prooven to be technical and chemo-ecologically possible. Heat Maps of stands with infested trees were generated in field trials and interpreted under additional information of the wind movement detected by a second drone.

This early detection concept can improve the fast response of foresters in order to protect conifer stands from bark beetle gradation. Further work is dedicated to the complete automation of the sensor drone flight and the Heat Map generation in order to transfer the measuring concept into the operational flow of forest management.

  • Open access
  • 25 Reads
Feasibility of sustainable management of secondary Atlantic Forest: Recovery and mortality rates of damaged trees two years after harvesting

Subject to over exploitation in the past centuries, the Atlantic Forest is now strictly protected including a ban on timber harvesting. However, this strict protection is a very controversial issue. It resulted in a lack of willingness of landholders to conserve and possibly even expand native forest areas. The lack of knowledge on impacts of potential timber-harvesting causes conflicts between conservation and management of the remnant Atlantic Forest. We believe that sustainable forest management, with reduced harvesting impact, has the potential to generate income for the landowners while sustaining important ecological services of the forest. Therefore, we assessed the harvesting impact of a conventional harvesting method (CM) and compared it to an alternative harvesting method (AM) in three different stands. We measured damage intensities of all remnant trees directly after harvesting and two years after harvesting. Tree damages were recorded at three different tree zones (crown, bole and leaning) and rated in three different intensity classes (minor, moderate and severe). Furthermore, we assessed the recovery and mortality rates of each damaged tree two years after harvesting. While most of the damages caused by CM were moderate to severe, damages caused by AM were light to moderate. Recovery of damaged trees is low, in general, especially at high degree crown damages. Moreover, tree mortality is high in stands with high density of smaller trees and high density of improvement felling.

  • Open access
  • 21 Reads
Direct assessment of biomass productivity in short rotation forestry (SRF) with the terrestrial laser scanner (TLS). Case of study in NE part of Romania (preliminary results).

Short rotation forestry (SRF) provides an important supply of biomass for investors in this area. In the NE part of Romania at the present time are installed over 800 Ha of this kind of crops. The SRF enjoys the support through environmental policies, in relation to climate change and the provisions of the Kyoto Protocol to reduce the concentration of CO2 in the atmosphere. A precise estimate of biomass production is necessary for the sustainable planning of forest resources and for the exchange of energy in ecosystems.
The use of the terrestrial laser scanner (TLS) in estimating the production of above ground wood biomass (AGWB) of short rotation forestry (SRF) brings an important technological leap among indirect (non-destructive) methods. TLS technology is justified when destructive methods become difficult to implement and allometric equations do not provide accurate information.
The main purpose of the research is to estimate the biomass productivity on tree parts in short rotation forestry with TLS technology. Measuring the hybrid poplars crops by TLS may have the following consequences:
- higher accuracy of the estimate of biomass production in the SRF;
- cost and time effective measurements over the biomass of tree parts;
- new and validated allometric equations for SRF in NE Romania;
- solid instrument for industry to estimate biomass.

TLS technology gives accurate estimates for DBH, tree height and location, as much as the volume on segments, commercial volume or crown volume can be determined. The accuracy of these values depends on the original scan data and their co-registration.
The research will contribute to the development of knowledge in the field of hybrid crops.