Skip to main content
SLU publication database (SLUpub)
Research article - Peer-reviewed, 2006

Effects of mulching and insecticides on establishment and growth of Norway spruce

Johansson K, Orlander G, Nilsson U


Establishment of Norway spruce (Picea abies (L.) Karst.) seedlings is often restricted by competition from vegetation, drought, and damage by pine weevils. In this study, effects of mulching on these factors were investigated. Norway spruce seedlings were planted on fresh and 1-year-old clearcuts treated with mulch on three sites in southern Sweden. Mulch was made of slash from the old stand and applied on whole blocks at three different depths: 0, 10, and 20 cm. Both insecticide-treated and untreated seedlings were planted. By reducing the competing vegetation and improving soil moisture and mineralization, mulching created a favorable growth environment. Mulching significantly improved growth in terms of height, diameter, and volume of the seedlings. Growth continued to increase over time in mulched treatments, probably as an effect of increased nutrient availability. The 20 cm mulch layer generated the greatest increase in growth throughout the 10-year experimental period. Soil moisture was preserved under the isolating mulch layer and during periods of drought soil water potential was significantly higher in mulched treatments. After 2 years, percent cover of competing vegetation was 50%-60% without mulch and 10%-20% with a mulch depth of 20 cm. Insecticide-treated seedlings achieved a survival rate close to 100% in all mulching treatments, whereas survival among untreated seedlings was only 40% on some clearcuts. Mulching alone did not affect survival or abundance of pine weevils

Published in

Canadian Journal of Forest Research
2006, Volume: 36, number: 10, pages: 2377-2385