What is it about?
Forest inventories are evolving towards multipurpose resource surveys, broadening their scope by including additional topics such as biodiversity issues. Surprisingly, few quantitative surveys have been devoted to old-growth forests, even if they constitute the most acknowledged forest biodiversity icons. In this framework, the use of probabilistic sampling may provide an effective as well as rigorous support for monitoring and assessing old-growth forests. To this purpose, the present paper proposes a two-phase sampling scheme. In the first phase, a coarse survey of few floristic and stand structural attributes is carried out by means of small plots systematically placed on the study area. Subsequently, in the second phase, a fine assessment of a large number of ecological attributes is performed on a subset of enlarged plots selected among the first-phase ones by means of simple random sampling without replacement.
Featured Image
Why is it important?
The use of probabilistic sampling constitutes the only way to ensure that the gathered information is scientifically defensible and as such it provides an effective support in monitoring and assessing natural resources. It is apparent from the literature that probabilistic schemes of sampling are preferred to purposive schemes at least for analytical environmental surveys, since they allow for non-controversial estimates which can be subsequently adopted in change detection, statistical comparisons as well as in extrapolation and forecasting techniques.
Perspectives
Sampling strategies which typically and traditionally characterize forest ecosystem inventories are well developed and readily available to the users. However, many disciplines, like landscape design, recreation planning, environmental impact assessment, and so forth, which currently influence land use decisions and use forest inventory data, often have relatively little background and experience with statistical sampling; rather they are more accustomed to case studies or the examination of so-called typical areas (purposive sampling). This may cause problems with the correct interpretation of the results arising from surveys based on probability sampling. On the other hand, the exploitation of tools like probability sampling will distinctively bring unique benefits, making further room for an effective integration among different survey sectors towards a comprehensive environmental monitoring and assessment. This is truer if accomplished by simple, flexible, and adaptive approaches apt to continuous upgrading in relation to the information needs and incorporation of multidisciplinary perspectives. The two-phase sampling here proposed seems to fulfill these requirements.
Piermaria Corona
CREA Research Centre for Forestry and Wood
Read the Original
This page is a summary of: Monitoring and assessing old‐growth forest stands by plot sampling, Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology, March 2010, Taylor & Francis,
DOI: 10.1080/11263500903560710.
You can read the full text:
Contributors
The following have contributed to this page
