Assessment of load and quality of logging residues from clear-felling areas in Järvselja: a case study from Southeast Estonia

Abstract

The properties of biomass-based fuel and combustion tests showed that logging residues are promising renewable energy sources. The data used in this study were collected from four clear-felling areas in Järvselja Training and Experimental Forest Centre, Southeast Estonia in 2013–2014. Logging was carried out by harvesters in Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies [L.] Karst.), silver birch (Betula pendula Roth.) and black alder (Alnus glutinosa L. Gaertn.) dominated stands with a small admixture of other tree species according to the cut-to-length method and logging residues were placed in heaps. The aim of this research is to assess different characteristics of logging residues (quantity, moisture content, energetic potential, ash content and amount) in clear-felling areas. The highest load of slash was measured on the birch dominated study site, where the dry weight of the logging residues was 29 t ha−1. Only the branch fraction moisture content on the black alder dominated site (35.4%) was clearly different from respective values on other sites (21.6–25.4%). The highest calorific value of the residues was assessed with the residues from the birch dominated site, where in moist sample it was 365 GJ ha−1 and in dry matter 585 GJ ha−1. The heating value of the fresh residues is highest in coniferous trees. The highest ash content in branch segments was registered for the black alder dominated site. Järvselja data indicate higher quality in conifer dominated sites, yet a higher load of logging residues in broadleaf dominated stands.

Changes in Commercial Dendromass Properties Depending on Type and Acquisition Time

“…These values lay within the same range as the results of the authors' experiment for chips obtained in autumn and winter. The LHV for chips obtained in late autumn from naturally dried logging residues of Norway spruce and Scots pine was higher (14 GJ Mg -1 ) [35]. It was lower for black alder (12.5 GJ Mg -1 ) and silver birch (11.3 GJ Mg -1 ).…”

“…The moisture content of chips obtained from logging residues in Sweden was higher and was 50.6% immediately after harvesting, and then, it decreased with the storage period [34]. The moisture content of logging residues from various tree species, when dried in summer, was definitely lower and ranged from 23 to 36% for Norway spruce and Black alder, respectively [35]. The moisture content of short-rotation woody crop (SRWC) dendromass was also diverse.…”

Quality and Delivery Costs of Wood Chips by Railway vs. Road Transport

“…In a different study in Estonia, the LHV of logging residues of various tree species left at the logging site to dry in summer was higher in late autumn and was 14 GJ Mg −1 for Norway spruce and Scots pine. The LHV was lower for Black alder (11.3 GJ Mg −1 ) and Silver birch (12.5 GJ Mg −1 ) [26].…”

“…However, this is not surprising, as the value lay within typical ranges for this type of solid biofuel, and the moisture content in chips also exceeded 50% in winter in the current research. In a different study in Estonia, the moisture content in logging residues of various tree species left at the logging site to dry in summer was much lower in autumn and ranged from 23-36% for Norway spruce and Black alder, respectively [26].…”

Young Silver Birch Grows Faster and Allocates Higher Portion of Biomass into Stem Than Norway Spruce, a Case Study from a Post-Disturbance Forest

“…Thanks to fast growth, birches can play an important role in carbon sequestration at sites where other tree species hardly survive. Experience from Scandinavian and Baltic countries [19,20] suggests that birches can be economically relevant species with a variety of utilization possibilities. According to Tiebel et al [21], renewed interest in silver birch has been recently raised with regard to forest management at higher altitudes.…”