Effects of early cleaning on young Picea abies stands

Abstract

Young Norway spruce stands (Picea abies [L.] Karst) are typically cleaned of non-crop species on one or several occasions during young stand stage. In order to objectively evaluate the perceived benefits of early cleaning (EC), we studied the effects of EC on three study sites 2–2.5 years after receiving the treatment. Experiments were established as a randomised complete block design with a total of 40 blocks. Although height growth and mortality were not significantly affected, we found that EC substantially reduced canopy competition and, consequently, the mean diameter of released spruce grew 21–32% faster depending on the site. Furthermore, non-crop trees that were cleared during EC had fewer sprouts in two of the three sites and the sprouts were substantially smaller than the corresponding non-crop trees on control in all sites. EC can reduce the cost of pre-commercial thinning because EC reduced the estimated time needed for subsequent management by 18–49%. Thus, EC offers forest owners and managers an economically viable young stand management option.

Keywords:

• early cleaning
• release treatment
• Norway spruce
• sprouting
• young stand management
• clearing
• forest vegetation management

Acknowledgement

We thank Jussi Nuutinen, Pekka Rossi, Mervi Seppänen and Pekka Voipio for assisting with field experiments and Michael Hardman for revising the English.

Funding

The study was funded by the Foundation for Research of Natural Resources in Finland (Suomen Luonnonvarain Tutkimussäätiö), and the work was carried out at the Finnish Forest Research Institute Suonenjoki Unit.

Additional information

Funding

Funding: The study was funded by the Foundation for Research of Natural Resources in Finland (Suomen Luonnonvarain Tutkimussäätiö), and the work was carried out at the Finnish Forest Research Institute Suonenjoki Unit.