A tree survey is a formal, systematic process used to gather specific information about individual trees or groups of trees within a defined geographic area. This inventory informs the long-term management of the trees, guides decisions related to health and safety, and provides documentation necessary for development and construction planning. The survey moves from initial planning through physical data collection, health assessment, and finally, the preparation of a comprehensive report.
Preliminary Planning and Scope Definition
The first phase involves clearly defining the project’s boundaries and objectives before any field work begins. This initial step, known as scoping, establishes the precise area to be covered and the level of detail required for the assessment. For urban or large-area surveys, obtaining accurate base maps, such as topographical surveys or recent aerial imagery, provides a spatial context for the trees.
The scope dictates the equipment and resources needed for the field effort. Essential tools include GPS devices for location recording, diameter tapes for measurement, and field notebooks or digital applications for data logging. Establishing a clear numbering or tagging system is necessary to ensure every tree receives a unique identifier. This identifier links the physical tree to its digital data record and eventual map location, ensuring efficiency and consistency during data collection.
On-Site Data Collection and Inventory
Fieldwork begins with the systematic inventory of each tree within the defined scope. The first step is attaching a unique, non-damaging tag or marker, which serves as the permanent reference number for all collected data. Next, the species must be identified, recording both the common name and the scientific binomial name to ensure precision.
A fundamental measurement is the Diameter at Breast Height (DBH), the standard method for determining trunk size. This measurement is typically taken at 4.5 feet (1.37 meters) above ground level in the United States, though some international standards use 1.3 meters. Diameter tapes, calibrated to convert circumference directly into diameter, are wrapped around the trunk at this specific height, ensuring the measurement is perpendicular to the trunk’s axis.
Surveyors estimate the tree’s height and the average canopy spread, which describes the extent of the crown. Tree height is measured using instruments like clinometers or hypsometers, which use trigonometry to calculate vertical distance. Canopy spread is recorded by measuring the distance from the trunk to the drip line in four cardinal directions (North, South, East, and West). An average is then calculated to represent the tree’s overall footprint. Finally, the precise location of each numbered tree is recorded using GPS devices to capture coordinates for mapping purposes.
Assessing Tree Health and Condition
Once inventory measurements are complete, the assessment shifts to evaluating the tree’s physiological health and structural integrity, which requires arboricultural expertise. Overall tree vigor is assessed qualitatively by looking at indicators such as foliage density, leaf color and size, and the extent of new shoot growth. A tree displaying high vigor will have a full crown and exhibit growth typical for its species and environment.
Structural integrity is evaluated using frameworks such as the Visual Tree Assessment (VTA) method, which focuses on identifying external symptoms that indicate potential internal defects. Surveyors inspect the trunk, branches, and root collar for signs of decay, often manifesting as fungal fruiting bodies (mushrooms or conks) on the wood. They also look for structural defects like included bark, where the bark is folded inward at a junction, creating a weaker attachment point than a typical branch union.
Other observable weaknesses include longitudinal cracks in the stem, severe trunk lean, or poor basal flare, suggesting root problems or advanced decay at the base. The presence of pests or diseases is noted, along with the degree of deadwood in the canopy, which indicates stress or decline. Based on this inspection, the arborist assigns a condition or risk rating, which quantifies the tree’s long-term viability and the potential hazard it poses to surrounding targets.
Finalizing the Survey Report and Mapping
The final stage involves transforming the raw field data into a functional document. Data entry and quality control are performed immediately, transferring field notes and measurements into a digital database or spreadsheet to ensure accuracy. This digital schedule includes the tree number, species, measurements, health rating, and specific observations made during the assessment.
A fundamental component of the final product is the tree map, which links the numbered inventory to their spatial locations using the recorded GPS coordinates. Geographic Information System (GIS) software is utilized to create a scaled plan that accurately depicts the location and canopy spread of every surveyed tree. This visual representation is necessary for planning, allowing users to understand the spatial relationship between the trees and any proposed development or management zones.
The final report includes a summary of the findings, the methodology used, the data table, and the final map. The report concludes by outlining specific management recommendations for each tree, informed by the assessment of health and structure. These recommendations may include immediate actions like pruning deadwood, installing mechanical support systems, establishing protection zones for retained trees, or recommending removal for trees deemed to present an unacceptable risk.