Overview of Forest Health Monitoring (FHM) Protocols
Prior to 1999, the USDA Forest Service administered two major programs to inventory and monitor the nation's forest resources: the Forest Inventory and Analysis (FIA) program, and the Forest Health Monitoring (FHM) program. As a result of new legislation and a revised implementation strategy, these two programs are now being merged, whereby more intensive measurements using the former FHM indicators and methodology are now being used in a subset of plots that are referred to as Phase 3 plots. Many of the protocols and specific methodologies used in the FIA program may be of interest to national parks as they develop their monitoring programs.
The following document gives an overview of the overall sampling framework and the types of data collected with the new merged program:
Summary of FHM Indicators:
More information on FIA indicators is available.
What are the advantages of using FIA protocols instead of custom-designed protocols?
Information on the strategy for combining the FIA and FHM programs, and details of plot design, methodology and other information can be obtained at FIA Program
The following document gives an overview of the overall sampling framework and the types of data collected with the new merged program:
Phase 1:
Phase 1 is the aspect of data collection related to remote sensing. We conduct this activity in the office. Current methods rely on aerial photographs:
- A Phase 1 "photo point" is evaluated for approximately every 240 acres.
- Each "photo point" is characterized as forest or nonforest.
- A subset of the photo points are selected for field data collection (Phase 2).
- A subset of photo points are also ground checked by the field crews during the Phase 2 data collection. It is from these ground checks of Phase 1 "photo points" that the forest/nonforest proportions are corrected to use in data processing.
We are currently changing from aerial photographs to satellite imagery for doing Phase 1 stratification.
Phase 2:
Phase 2 is the field data collection activity. The field plots are selected systematically regardless of whether they are forest or nonforest in Phase 1. Forested plots are installed and measured regardless of intended use or any restrictive management policy. Plots are also installed on all ownerships after permission is granted by the landowner. It is on these field locations that the majority of data collection activities occurs.
- All tree measurements such as diameter, height, damage, cull, and grade;
- Counts of tree regeneration;
- General land use is determined on all plots.
- On forested plots, general stand characteristics are also collected such as forest type, stand age, and disturbance.
- By remeasuring plots from the previous time frame, estimates of growth, mortality, and regeneration are made at both the tree and plot level.
- Changes in land use and general stand characteristics are determined by revisiting plots from the previous time period.
Phase 3:
On a subset of the Phase 2 plots, we collect a more extensive set of data. These measures relate to forest ecosystem function, condition, and health. Due to the seasonality associated with some of these measurements, the Phase 3 data are generally collected during a three-month window – June, July, and August. The current measurements on the Phase 3 subset of plots can be grouped into the following categories:
- Crown Conditions – generally poor crown conditions are symptoms of trees under stress and trees with good crown conditions are vigorous.
- Soil Erosion Potential – estimates of soil erosion potential help identify areas that may contribute to water quality degradation.
- Soil Chemical Analyses – collection of and analysis of soil samples include estimates of site fertility and in some cases potential toxicity relating to acidic soils that relate to productivity.
- Lichen Communities – the presence or absence of certain lichen species is indicative of air quality and climate changes.
- Ozone Bioindicator Plants – are plants with know sensitivities to ground-level ozone, although not necessarily collected on the Phase 3 plots (this effort can occur in the general plot area).
- Vegetation Structure – is the composition of vegetation (species and growth forms), abundance, and spatial arrangement in the forest. Also the presence of exotic and introduced plant species can be extracted from the collected data.
- Down Woody Debris – this measurement is useful in determining fire fuel potential and this information with the vegetation structure data can be used in wildlfe habitat models.
Summary of FHM Indicators:
- Crown Condition: crown diameter, live crown ratio, crown density, crown dieback, foliage transparency, crown vigor.
- Tree Damage: presence of decay, disease, breakage, discoloration.
- Tree Growth: dbh of saplings and trees.
- Tree Mortality: dbh of trees that have died since last plot visit.
- Tree Regeneration: seedling and sapling counts by species
- Ozone damage: % of damaged foliage on indicator plant species
- Lichens: abundance as bioindicator of changes in air quality, climate, forest structure.
- Soils: soil erosion, soil nutrients (carbon storage, N, P, Ca, Mg, K).
- Vegetation Diversity and Structure: nested plots; number and density by species, height; % groundcover; presence/density of exotic species.
- Down Woody Debris: number and volume of dead tree parts.
- Fuel Loading: % cover and depth of grass, shrubs, slash & litter for fuel models.
- Wildlife Habitat: snags, plot composition and structure.
More information on FIA indicators is available.
What are the advantages of using FIA protocols instead of custom-designed protocols?
- Use of FIA protocols would allow a park to compare their data to areas outside the park, both locally and regionally. This helps to put park data in context and allows comparisons to be made both spatially and temporally. By adding the spatial dimension, problems may be identified earlier than if only the temporal dimension were available.
- FIA protocols provide information relevant to park management issues, such as monitoring invasive species, forest insect and disease issues, structure and composition of understory vegetation, and fuel loading. All of the measurements made by a park that custom-designed its own forest plot monitoring protocols are included in the FIA protocols, and yet because of sampling efficiencies, FIA plots provide a greater number of measurements at lower cost than custom-designed protocols. The estimated cost of following FHM protocols is about $800 - $1200 per plot in the continental US, depending on housing, travel costs, and region of the country.
- The protocols for the data collected in Phase 3 plots have been peer-reviewed and field-tested since 1990. Quality assurance is an important part of the program. This includes Measurement Quality Objectives (precision objectives) for each individual measurement, an annual training program for field personnel, field audits to ensure that measurements are consistent and meet the MQO's, and data management procedures designed to reduce data collection, analysis, and reporting errors.
Information on the strategy for combining the FIA and FHM programs, and details of plot design, methodology and other information can be obtained at FIA Program