Stakeholder valuation of soil ecosystem services from New Zealand's planted forests.

The goal of this study was to determine if there were differences among stakeholders in the values they attribute to soil ecosystem services from plantation forests in New Zealand. Groups of forest-associated stakeholders were identified (e.g. land owners, forest owners, wood processors, and recreational forest users) and surveyed to assess their cultural background (indigenous New Zealand Maori or not) and then the relative importance they placed on 10 forest soil ecosystem services. Across all survey respondents, very high importance was placed on the ability of soils to sustain forest growth across multiple plantings/rotations (sustainable production). Interestingly, this was more highly valued than maximising short-term production. Maori placed greater importance on forest ecosystem resilience, provenance and kaitiakitanga (sensu stewardship of resources), water quality, and harvest of food and/or medicines from forests than non-Maori. These results demonstrate inherent cultural differences in valuing the range of forest ecosystem services that soils support. It is important that cultural views are understood and integrated into future soil health testing schemes to reflect the needs of all stakeholders. Ultimately, this work will help increase the sustainability of planted forest ecosystems in New Zealand, ensure the forestry sectors social licence to operate, and add value to forest products by demonstrating environmental and cultural stewardship of forest products.

Nitrogen cycling in canopy soils of tropical montane forests responds rapidly to indirect N and P fertilization.

Although the canopy can play an important role in forest nutrient cycles, canopy-based processes are often overlooked in studies on nutrient deposition. In areas of nitrogen (N) and phosphorus (P) deposition, canopy soils may retain a significant proportion of atmospheric inputs, and also receive indirect enrichment through root uptake followed by throughfall or recycling of plant litter in the canopy. We measured net and gross rates of N cycling in canopy soils of tropical montane forests along an elevation gradient and assessed indirect effects of elevated nutrient inputs to the forest floor. Net N cycling rates were measured using the buried bag method. Gross N cycling rates were measured using (15) N pool dilution techniques. Measurements took place in the field, in the wet and dry season, using intact cores of canopy soil from three elevations (1000, 2000 and 3000 m). The forest floor had been fertilized biannually with moderate amounts of N and P for 4 years; treatments included control, N, P, and N + P. In control plots, gross rates of NH4 (+) transformations decreased with increasing elevation; gross rates of NO3 (-) transformations did not exhibit a clear elevation trend, but were significantly affected by season. Nutrient-addition effects were different at each elevation, but combined N + P generally increased N cycling rates at all elevations. Results showed that canopy soils could be a significant N source for epiphytes as well as contributing up to 23% of total (canopy + forest floor) mineral N production in our forests. In contrast to theories that canopy soils are decoupled from nutrient cycling in forest floor soil, N cycling in our canopy soils was sensitive to slight changes in forest floor nutrient availability. Long-term atmospheric N and P deposition may lead to increased N cycling, but also increased mineral N losses from the canopy soil system.