The contribution of limited-focus land-use programmes in the provision of ecosystem services in New Zealand

Abstract

A common approach in the provision of Ecosystem Services (ES) is to develop comprehensive ES markets or establish payments for ES, both of which are complex and costly. As an alternative, this research has focused on (i) ES provided by different types of single or limited-focus, land-use programmes, (ii) people's preferences for different ES and effect on relative ES from single or limited-focus land-use programmes, and (iii) relative cost of delivering ES from single or limited focus land-use programmes. To achieve these objectives, this research studied the ES from an afforestation (plantation) project and a reforestation project, either or both of which could arise from three forest-related programmes in New Zealand, the New Zealand Emissions Trading Scheme or ETS (a market approach), the East Coast Forestry Project (ECFP) (a subsidy/regulation approach), and the QEII National Trust (a partial subsidy through an NGO approach). Each programme provides incentives to landowners to plant and/or conserve trees on their lands to meet particular ES objective(s), but which also produce other ES. The impacts of the plantation forestry and natural reversion scenarios on flows of six ES – timber production, carbon sequestration, maintenance of water quality, regulation of water flow, soil erosion control, and natural habitat provision – were studied. For this purpose, biophysical models and a habitat function developed in New Zealand were used for estimating flows of ES (bio-physical assessment). Analytical Hierarchy Process and Max100 methods were used to derive preference weights for the flows of ES from members of the public (social assessment). The Kaituna catchment in the Banks Peninsula was selected for the study site as it is on the Environment Canterbury list of potential flow-sensitive catchments. The results of converting steep, Class 4 and above land (about half of the catchment area) from existing sheep and beef grazing to iii plantation forestry or to scrubland enhances a number of ES, namely climate regulation, water quality, erosion control, and natural habitat provision. However, water yield decreases by about 21 and 10 percent respectively in the plantation forestry and scrubland scenarios (an indicator that may be relevant in other low rainfall areas). Using a cumulative indicator score of all ES flows measured, calculated by normalising ES outputs for each land-use scenario, the plantation forestry scenario showed a higher combined ES flow score (1.88) than the scrubland scenario (1.39). The main reason for this is that timber revenue is foregone in the scrubland scenario and scrub stores less carbon than does plantation forests. The research also assessed three extreme (and less likely to occur) land use scenarios, in which all the land available in the catchment except Department of Conservation land, were converted to either plantation forestry, scrubland, or exotic pastures (dairy). In the extreme scenarios, an ‘all plantation forestry’ scenario gives the highest cumulative ES indicator score (2.77) whereas an ‘all pasture (dairy)’ scenario gives the lowest cumulative indicator score (-1.84).