Labour consumption models applied to motor-manual pre-commercial thinning in Finland

Abstract

, Kiljunen N. (2014). Labour consumption models applied to motor-manual pre-commercial thinning in Finland. Silva Fennica vol. 48 no. 2 article id 982. 14 p. Highlights• When a young stand grows and gets older, the work time needed to make pre-commercial thinning increases. The stands of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and hardwoods (Betula spp.) required an additional 8.2%, 5.2%, and 3.3% work-time per year, respectively. AbstractLabour models were developed to estimate the time required to Pre-Commercially Thin (PCT) with a clearing saw 4-to 20-year-old stands of the main commercial tree species in Finland. Labour (i.e., work-time consumption) was estimated from the density and stem diameter of the removal of 448 stands via an existing work productivity function. The removal based estimator attained was used as the basis for a priori mixed linear regression models. The main finding was that when a young stand grows and gets older, the work time needed to make a PCT increases. The stands of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and hardwoods (Betula spp.) required an additional 8.2%, 5.2%, and 3.3% work-time per year, respectively. Site fertility also played a role in that the most fertile site (mesic OMT) had an estimated labour requirement 114% higher than that for dryish VT. We also note that, per unit area, small stands require less labour than large ones and soil preparation method had a minor effect on the labour estimate. The stands which had previously gone through PCT were separately analysed. In those stands, the only significant variable concerning the labour estimate was age. The a priori models described here can help foresters to develop economic management programmes and issue quotes for forestry services.

Time consumption and productivity in manual tree felling with a chainsaw – a case study of resinous stands from mountainous areas

“…Tree size is the main characteristic influencing tree felling with a mechanical chainsaw. Most research uses dbh as the main factor for estimating productivity and worktime either by linear equations (Samset 1990;Ghaffarian and Sobhani 2007;Uotila et al 2014) or by the power function (Peterson 1987;Lortz et al 1997;Liepiņš et al 2015) and sd in an exponential model.…”

“…The dependency of felling time on tree breast height diameter is expressed by linear (Samset 1990;Ghaffarian and Sobhani 2007;Uotila et al 2014) or nonlinear (Peterson 1987;Lortz et al 1997) correlations. The complexity of the tree felling operation with the chainsaw led to the analysis of its every stage with respect to time consumption (Nurminen et al 2006;Azarnoush and Fathi 2014).…”

Low cost prediction of time consumption for pre-commercial thinning in Finland

“…The precision and expenses of WSC increase with the number of plots required. The expenses may be high compared to a PCT of a rather easy worksite, which takes about 4-10 h ha -1 to do (Koskinen 2013;Uotila et al 2014). Thus, WSC-methods used in practice are likely to be much less time demanding.…”

Effect of wood ash mulch on growth of Scots pine seedlings after transplanting into peat soil: A pilot study

“…On peatlands, Scots pine is a commonly grown tree species and ditch mounding is the major soil preparation method used with the arrangement of drainage (Pearson et al 2011;Luoranen, Viiri 2012;Hökkä et al 2016). Soil preparation enhances post-planting seedling growth but can also enhance the germination of such tree and shrub species that will later compete with the planted saplings (Raulo, Mälkönen 1975;Johansson et al 2013;Uotila et al 2014). Thus, the need for tending and release treatments can become critical and more labour intensive (Uotila et al 2012(Uotila et al , 2014.…”

“…Soil preparation enhances post-planting seedling growth but can also enhance the germination of such tree and shrub species that will later compete with the planted saplings (Raulo, Mälkönen 1975;Johansson et al 2013;Uotila et al 2014). Thus, the need for tending and release treatments can become critical and more labour intensive (Uotila et al 2012(Uotila et al , 2014.…”