Treesearch

Although design and estimation aspects of annual forest inventories have begun to receive considerable attention within the forestry and natural resources communities, little attention has been devoted to identifying the sources of uncertainty inherent in these systems or to assessing the impact of those uncertainties on the total uncertainties of inventory estimates. A brief overview of the annual forest inventory system under development for the North Central region is provided, sources of uncertainty within the required components are identified, and their magnitudes and impacts on...

Annual forest inventory systems in the United States have generally converged on sampling designs that: (1) measure equal proportions of the total number of plots each year; and (2) call for the plots to be systematically dispersed. However, there will inevitably be a need to deviate from the basic design to respond to special requests, natural disasters, and budgetary fluctuations. Some simple methods for maintaining a flexible panel design and implementing a moving average estimator are discussed.

Analytical tools are needed to evaluate the impact of management policies on the sustainable use of rain forest. Optimal decisions concerning the level of management inputs require accurate predictions of output at all relevant input levels. Using growth data from 40 l-hectare permanent plots obtained from the semi-deciduous forest of Ghana, a system of 77 differential equations was developed to quantify the growth dynamics of the mixed-species rain forest. The models underlying the equations were developed for seven species groups, each with similar growth characteristics. This minimized...

Greater demands on forest resources require that larger amounts of information be readily available to decisionmakers. To provide more information faster, databases must be developed that are more comprehensive and easier to use. Data modeling is a process for building more complete and flexible databases by emphasizing fundamental relationships over existing or traditional business operations. Data modeling uses a hierarchical series of models beginning with a conceptual model of the activity of interest. From the conceptual model, a logical model is derived that captures more detail, but...

To support the management of the Portuguese eucalyptus forest, the Association of Portuguese Pulp and Paper Industries (CELPA) decided to develop a Eucalyptus Forest Information System (EFIS). The specific goals of the EFIS are: characterization and development of the eucalyptus forest over time; planning of successive national eucalyptus forest inventories; estimation of sustainable eucalyptus pulpwood yield; development of growth and yield models; and monitoring of mean and current annual increment. This paper gives a concise image of the Portuguese eucalyptus forest and explains the...

Stand dynamics in European strict forest reserves are commonly monitored using inventory densities of 5 to 15 percent of the total surface. The assumption that these densities guarantee a representative image of certain parameters is critically analyzed in a case study for the parameters basal area and stem number. The required sample sizes for different accuracy and probability levels are calculated. The commonly applied inventory densities prove to be insufficient for both parameters considering a generally desired accuracy level of 5 percent (p = 0.05). Results indicate the need for a...

International forest statistics such as those provided by the UN/ECE-FAO Temperate and Boreal Forest Resource Assessment (TBFRA) are typically compiled from national surveys. However, the national systems of nomenclature as well as the definition of the attributes often vary considerably. The European Commission, DG VI, initiated a study to investigate the potential of a European Communication and Information System (EFICS). In the framework of the EFICS study, the effect of different definitions of forest key attributes was investigated. The main focus was on the forest area and growing...

The Southern Research Station is currently implementing an annual forest survey in 7 of the 13 states that it is responsible for surveying. The Southern Annual Forest Inventory System (SAFIS) sampling design is a systematic sample of five interpenetrating grids, whereby an equal number of plots are measured each year. The area representative and time series nature of the SAFIS plot design offers increased flexibility in analyzing the data for both large- and small-domain means. Users of FIA information are often interested in the estimates of small-domain means, at the multi-county or FIA...

DataPlus allows the user to easily design data collection templates for DOS-based hand-held computers that mimic clipboard data sheets. The user designs and tests the application on the desktop PC and then transfers it to a DOS field computer. Other features include: error checking, missing data checks, and sensor input from RS-232 devices such as bar code wands, calipers, electronic balances, GPS receivers, laser rangefinders, and water quality transmitters. DataPlus is developed for the nonprogrammer, yet robust enough for the professional software developer. DataPlus was designed with...

Rapid and reliable estimation of leaf area at various scales is important for research on chance detection of leaf area index (LAI) as an indicator of ecosystem condition. It is of utmost importance to know to what extent boundary and illumination conditions, data aggregation method, and sampling scheme influence the relative accuracy of stand-level LAI measurements. This knowledge should lead to a high repeatability and relative accuracy of the LAI measurements. In this research, LI-COR is recorded with a Licor LAI-2000, one of the more modem and widely used plant canopy analyzer instrumen...