Early Intervention for Invasive Ailanthus altissima in Angeles National Forest Watersheds

Agriculture Access has spent a number of years observing, monitoring, and hiking within the Texas Canyon watershed. Based on communications with both the Angeles National Forest and the Mountain Recreation and Conservation Authority (MRCA), who jointly own and manage portions of the Texas Canyon watershed, it seems likely that conservation of this watershed region is a high priority. Therefore, an investment in an invasive weed control project for the control and prevention of Tree of Heaven populations makes common sense over the long-term. By targeting both the largest ‘parent trees’ (having the tallest, most mature leaf canopies) and newest ‘root sprouts’ (having the most active growing leaf canopies) within this half-acre site, the project proposes to “suppress photosynthesis” and its “source-sink” relationship. By selecting the use of Integrated Pest Management (IPM) protocols that remove large parent canopies and root sprouts, and “block sunlight” over periods of 3-6 months to prevent their regrowth, the control of this invasive weed site will be achieved. Without sufficient sunlight, Tree of Heaven is unable to assimilate carbohydrates and distribute them to newly growing root sprouts. Thus, severely hindering new growth or expansion of the weed site. The main advantage of early intervention of Tree of Heaven weed sites, is that the population size is small (<1.0 acre), is thus is economically feasible and efficient to control and manage over the long-term. If by controlling photosynthesis within leaves, crowns, and root sprouts of this Tree of Heaven weed site at an early-intervention stage of development, then it should be feasible to stop the expansion, and arrest the growth of the entire site within the Texas Canyon Watershed.