The impact of shelterbelts in North Island East Coast dryland regions

Abstract

Shelterbelts are a feature of the New Zealand landscape and in the dryland East Coast regions of the North Island, are seen in a diversity of planting patterns, species and silvicultural practices. To date, their economic benefits have not been assessed, partly because of the difficulty in evaluating the many interrelated pasture, soil, animal and forestry factors. Recent shelterbelt research in New Zealand has been conducted as a collaborative approach by AgResearch, Forest Research and Hort Research. Results of pasture, soil and tree measurements in the East Coast region indicate that shelterbelts, however managed, do not significantly increase pasture production in the sheltered zone. The competitive effects of trees reduce soil moisture in zones close to the shelter, which also encourages the accumulation of dung and urine nutrients in this zone by animals seeking protection. The modification in resting patterns as a result of shelter may be reflected in improved animal welfare and production but this was not measured. The value of timber from shelterbelts on the East Coast indicates that they have a role in diversifying farming income and offering a modified land use, which will help to sustain productive farming practices. Keywords: livestock, log value, pasture production, Pinus radiata, shelter, shelterbelts, soil moisture, soil nutrients, wood yields