Estimating the need for early cleaning in Norway spruce plantations in Finland

Abstract

Effective management of Norway spruce (Picea abies (L.) Karst.) plantations requires detailed information on stand development, which is costly to measure. However, estimating the need for early stand management from site attributes that persists stabile after ones measured, may provide an inexpensive alternative. This study compared hardwood competition in spruce plantations of varying ages and tested the usability of this information in estimating the need for early cleaning.The data included 197 spruce plantations (4-7 years old) inventoried in southern Finland in 2007. The level (Low, Substantial, High) of need for early cleaning was subjectively determined by contrasting location and size of competing hardwoods to a conifer crop tree. Then the stage of the need for early cleaning was modelled according to site and stand attributes.Nearly 60% of the conifer crop trees in the plantations were subjectively judged to require early cleaning (Substantial 37.2%, High 21.2%), but only 10 per cent of the evaluated area was cleaned. Need for cleaning was intense on peatlands or damp soils, whereas it was mild on unprepared soils or cleaned sites. Traditional site characteristics used in forest management planning can be useful for recognising the peripheral cases, where need for cleaning is probably high or low. However, on a typical mineral soil plantation (uncleaned, soil prepared) the model indicates the differences in the need for early cleaning weakly.The need for early cleaning was already high in 4-year-old plantations, why stand age did not have significant effect on development of the need. Thus, the timing of an operation can not be predicted with the model. Nonetheless, early cleaning very likely opens growth space of crop trees in a 4-7-year-old spruce plantation. Therefore, from an aspect of crop growth, an uncleaned Norway spruce plantation in this age group is quite consistently worth cleaning.

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

“…This is similar to the effect soil preparation technique has on the need for early cleaning (Uotila et al, 2012). However, this result is unexpected because a preparation method that exposes a lot of mineral soil (i.e., continuous trace) typically leads to the emergence of many hardwood seedlings (Uotila et al 2010).…”

“…However, in practice hardwoods are often removed too late to gain the most benefit from it (Uotila et al 2012;Uotila and Saksa 2013).…”

Effects of early cleaning on youngPicea abiesstands

“…According to Uotila et al (2012), while ca. 60% of the saplings in 4-to 7-year-old Norway spruce stands required EC, only ca.…”

Real-time detection of young spruce using color and texture features on an autonomous forest machine

“…In addition, the cleaning operation can be carried out chemically. However, it has some environmental concerns and a strong public opposition [4]. Point cleaning is a practical precommercial thinning method, in which the cleaning is performed within a certain radius Manuscript around the main stem [5].…”