Volunteers have been surveying the natural areas of the parks and assigning them grades based on what percentage of the trees are threatened by invasive vines, how badly invasive plants are preventing access to our parks, and how much of the park is being overrun. (If you have experience with invasive plant identification and would like to help with the surveys, see this page.)
Invasive vines threatening trees
Approximate percentage of trees at serious risk from invasive vines (either way up in the canopy, or girdling the trunk). Include trees that are more than a few feet high.
Blue - Great! - Few or no invasive vines on the trees.
Yellow - Could be better - Vines are on the trees but not yet girdling or way up in the canopy, or on only a very small percentage.
Orange - Getting bad - Vines seriously threaten up to a quarter of the trees
Red - Terrible - More than a quarter of the trees are under serious threat.
Access to parks (as affected by invasive plant infestations)
Evaluate the accessibility of the "natural" parts of parks - exclude developed areas such as ballparks, buildings, lawns, etc.
Blue - Excellent (Accessible) - Invasive species are present at very low levels and do not impede access. Trails and use areas are fully open and easy to navigate.
Yellow - Good (Slightly Impeded) - Invasive species partially restrict movement. Trails or access points may be narrowed or lightly obstructed, causing minor inconvenience but remaining passable. There may be a few isolated areas that are inaccessible, but the majority of the area is passable.
Orange - Getting bad (Moderately Impeded) - Invasive species significantly hinder access. Movement beyond trails or developed areas requires detours, stepping over or pushing through vegetation, or may discourage some visitors. Portions of the area are difficult to reach.
Red - Bad (Inaccessible) - Dense invasive cover blocks or closes access entirely. The area is effectively impenetrable and cannot be used without major clearing.
Overall severity of invasive plants
Evaluate the degree of invasion of the "natural" parts of parks - exclude developed areas such as ballparks, buildings, lawns, etc.
Blue - Invasive nonnative plant species apparently absent. Invasive plants are not noticeable even when looking carefully. Native plants dominate every visible layer.
Also Blue - Very Good - Invasive nonnative plant species present but sporadic (1–3% cover). Occasional invasive plants or small clumps occur here and there. They’re widely scattered, not forming patches, and most people would overlook them on a casual walk.
Yellow - Good - Invasive nonnative plant species somewhat common (4–20% cover). Invasive plants are present in repeated patches. They’re noticeable but not overwhelming—for example, scattered clusters along a trail or in openings, but still a minority of the vegetation
Orange - Getting bad- Invasive nonnative plant species common (21-50% cover). Invasive plants are easy to find and present in many parts of the site. They may form frequent patches or partial carpets, and natives are clearly being displaced in some areas.
Red - Bad - Invasive nonnative plant species abundant (>50% cover). Invasive plants dominate large areas, sometimes forming continuous or nearly continuous cover. You may see monoculture-like patches, with natives noticeably reduced or absent.