Modelling roundwood assortment yield in thinning of birch plantations on former farmland

Transcription

1 Modelling roundwood assortment yield in thinning of birch plantations on former farmland Liepiņš Kaspars, Donis Jānis, Liepiņš Jānis LSFRI Silava Rigas str.. Salaspils LV 2169 Latvia Phone: Fax:

2 Birch commercially important tree species in Latvia Birch is most important broadleaved tree species in Latvia covering 30.6% of total forest area. Felling volume 3.5 million m 3 in Production amount of birch plywood exceeded m 3 in 2013.

3 Establishment of birch plantations on former farmlands Afforestation of surplus agricultural lands with birch started in the beginning of this century. Since that. around 1000 ha of birch plantations have been established yearly. At the end of the nineties the. so called. «Birch program» was launched. initiated by the biggest national plywood producer JSC Latvijas Finieris. The aim of the programme was to generate the new knowledge regarding management of birch stands and promote the birch as economically feasible tree species among forest owners. At the same time the birch breeding program was launched in Latvia. Currently the research on birch is focused on management of birch plantations to enhance the productivity and timber quality (thinnings. high pruning) and to explore the mechanical quality of the timber extracted from plantations.

4 Thinnings in birch plantations Proper timing of first thinning in birch plantations is essential to: maintain the productivity of the stand; ensure the profitability, providing early cash transaction. The aim of current study: To develop the tool that would enable the forest owners to predict the potential roundwood yield that can be extracted in first thinning of birch plantations.

5 Material Experimental plots Object Age, years Stem number DBH, cm Tree height, m Basal area, m 2 ha -1 Stand volume, m 3 ha -1 Gaigalava Iecava Iecava Mālpils Sabile Ukri Zante

6 Methods Stand diameter distribution (two-parameter Weibull distribution); Assortments structure (Ozoliņš, 2002*); Calculation of relative proportion of pulpwood (% of total harvested volume) for 594 theoretical stands; Modelling relative proportion of pulpwood using equation: ab + cdbhd Y = b + DBH d *Ozolins. R. (2002). Forest stand assortment structure analysis using mathematical modelling. Forestry Studies Metsanduslikud Uurimused Coefficient Value SE a b c d Equation SE R

7 Results Proportion of the pulpwood from total harvested timber in first thinning of birch plantations 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Stem volume, m 3

8 Pulpwood volume in first thinning of birch plantations measured vs calculated DBH, cm Tree height, m Stem number Volume of assortments, m 3 Difference Before After thinning thinning Measured Calculated m 3 %

9 Tool for predicting pulpwood and wood biomass outcome in first thinning of birch plantations

10 Thank you! This study was funded in part by the European Union s European Regional Development Fund (ERDF), Project No. 2013/0049/2DP/ /13/APIA/VIAA/031