Matching species to site

The NZDFI aims to produce micro-site suitability maps for selected eucalypt species. Different species of eucalypts have varying environmental restrictions which limit their growth. By modelling growth of various species as a function of topographic, edaphic (soil-related), and climatic site characteristics, we will improve our ability to select the most appropriate species for any given site.

Research programme and methods

There are three stages to our site x species modelling work:

  1. Measuring growth of trees over time
  2. Measuring site characteristics at a suitable scale
  3. Modelling the relationship between growth and site characteristics.

Measuring tree growth

We are measuring the growth of more than 20,000 eucalypt trees at various NZDFI trial sites. We are focusing on two species, E. bosistoana and E. globoidea, with ages ranging from 5– 13 years.

The height and diameter at breast height (DBH) for each tree will be measured at least two times to determine their growth over a specific time period.

On-site climate station.

On-site climate station.

Measuring micro-site characteristics

Characterising a site’s topographic, edaphic, and climatic is necessary to understand the environmental conditions that affect tree growth at each of the NZDFI trials. Macro-site descriptions are available from coarse-scale nationally available data, but the accuracy of these data are insufficient for micro-site species matching. For example, at a single planting site, the radiation received by trees on a north facing slope will significantly exceed the radiation received by trees on a south facing slope, but available coarse-scale data will not account for this difference. So we are undertaking micro-site characterisation at numerous dryland NZDFI trials.

 

Temperature logger.

Temperature logger.

High resolution, site-scale topographic maps are being developed to account for small changes in topography within growing sites. Changes in soil characteristics are being measured across topographic gradients within each site. For example, the soil moisture holding capacity is being measured at the top of a slope, mid-slope and on the toe of the slope, to understand how these edaphic differences can lead to differences in tree growth.

Finally, micro-site climatic data are being collected, in many cases hourly to better explain the temperature, radiation, precipitation, and wind variation within and across trial sites.

Soil moisture logger with GPS positioning.

Soil moisture logger with GPS positioning.

Digging soil pits.

Digging soil pits.

Soil sampling.

Soil sampling.

Soil moisture logger.

Soil moisture logger.

Research Plan

Our latest Site_Species Matching Research Plan is available here.

Key researchers

Dr Justin Morgenroth and  Professor Euan Mason are working together on the site-species matching research. We co-supervise one PhD student, Serajis Salekin.

 

More information

Visit the School of Forestry website to learn more about matching species to site research.