LAIDLAW Research Pilot
Abstract
Forest structure shapes the habitat available for important ecological processes such as regeneration, decomposition, and nutrient cycling. Many of the soil conditions and forest-floor processes connected with that structure are difficult for land stewards to assess directly without laboratory analysis. Visible features such as fallen deadwood, native woody species richness, and surface-litter depth are linked to these ecological functions and can be measured with ordinary field equipment. What practitioners lack is a practical basis for judging whether the values they measure are unusual for a New England forest. Drawing on regional forest data, a matched-scale forest census, and peer-reviewed ecological evidence, this project developed a pilot version of the Visible Habitat Profile (VHP), a reference-based structural assessment tool for land stewards.
The VHP establishes reference ranges for three habitat features that are ecologically meaningful, easy to measure, and responsive to forest stewardship. It allows a practitioner to translate raw field measurements into an interpretable comparison: a plot with four native woody species falls below the lower boundary of the Harvard Forest reference for the same 400 m² plot size, indicating that native woody richness may warrant greater management attention. The framework is supported by field instructions, a mobile app, a field datasheet, a workbook, and an interpretation guide, providing a practical way to record, calculate, and interpret results.
The framework places field measurements within explicit reference distributions and shows that ecological comparisons depend on how features are defined and which reference populations are used. The reference ranges are empirically derived but reflect design judgments rather than validated thresholds, and they can be revised as field use reveals areas for refinement in measurement, reference matching, and interpretation.
An independent northeastern dataset was used to explore whether the same measurements were associated with soil microbial biomass; it was not used to set the reference ranges. A four-site pilot field study was designed to test whether independent observers obtain reproducible VHP range classifications using the same standardized field protocol. In the completed pilot, the two observers assigned the same Low, Typical, or High classification on 8 of 8 paired plots for native woody richness and on 7 of 8 paired plots for both coarse woody debris volume and surface-litter depth, which meet the 6-of-8 reproducibility standard.
The Project demonstrates how existing ecological research and datasets can be adapted for practical field assessment. By synthesizing these materials and developing field protocols matched to the reference data, the VHP provides a pilot framework for giving practitioners usable information about visible habitat features, a first step toward bringing soil-related considerations into routine forest stewardship.
1. Introduction
Nature’s Pharmacy Project (the “Project”) began by considering the connection between forest soils and human health. Soil microbial communities help drive decomposition and nutrient cycling and have historically been an important source of antibiotic compounds. Yet these communities are not visible in routine forest assessment and are expensive to assess directly in the laboratory.
Research increasingly shows that aboveground forest features are linked to belowground microbial communities and forest-floor processes (Lang et al. 2023). This raised a practical question: could visible forest features that are ecologically relevant to those processes form the basis of an assessment framework for land practitioners?
Drawing on peer-reviewed temperate-forest research, forest census data, and regional forest inventory data, the Project evaluated candidate habitat features based on ecological relevance, practicality of field measurement, responsiveness to forest management, and availability of an appropriate basis for comparison. Existing forest monitoring programs contain extensive data, but their measurements are not automatically comparable with those collected by a practitioner. Establishing a useful reference therefore requires matching both the habitat feature and the way it is measured as closely as possible, while also accounting for differences in spatial scale and sampling design.
The Project developed a pilot version of the Visible Habitat Profile (VHP), which establishes standardized field protocols and reference ranges for three visible forest habitat features: native woody richness, coarse woody debris (CWD) volume, and identifiable surface-litter depth. These features were selected because the ecological literature links them, to differing degrees, with microbial biomass, fungal properties, enzyme activity, community composition, decomposition, moisture, and other forest-floor processes. Just as importantly, each can be measured using simple field methods, interpreted against existing forest data, and influenced through forest stewardship, including decisions about native regeneration, deadwood retention, invasive woody vegetation, and forest-floor disturbance.
The Project comprised four linked components that develop and initially test this pilot framework. First, the literature was reviewed to establish ecological relevance and measurement limitations of the three features. Second, comparable forest datasets were used to establish Low, Typical, and High reference ranges for each measurement. Third, an independent northeastern dataset from the National Ecological Observatory Network (NEON) was used to explore whether these habitat measurements were associated with microbial biomass. Fourth, a four-site field study was designed to test whether independent observers obtain reproducible VHP range classifications using the same field protocol.