Harris County Flood Control District Memorial Park Demonstration Project Vegetation Survey

Transcription

1 Summary Report Harris County Flood Control District Memorial Park Demonstration Project Vegetation Survey Prepared by: Consultants, LLC Land + Place Studio forestry - natural resource Planning December 16, 2013

2 John Watson Facili es Maintenance Manager Harris County Flood Control District Northwest Freeway Houston, Texas Consultants, LLC Land + Place Studio forestry - natural resource planning 310 Longmire Road, Conroe, TX P.O. Box 1424, Conroe, TX P: F: phoward@burditt.com Dear Mr. Watson, A ached is our summary report of findings for the Memorial Park Demonstra on Project - Vegeta on Survey. Herein is a summary of the methodology used in data collec on, tables of inventoried tree characteris cs, and narra ve descrip on of the general site condi ons and rela ve plant communi es iden fied. We have included a map atlas and a list of all species found during the course of our work. Digital files will be delivered to HCFCD for future planning and design work. Files will include a ESRI shapefiles of the field data, MSExcel spreadsheet of field data, digital photos (geotagged for mapping reference) and a copy of this report. It has been a pleasure to work with your team on this project. We are free to answer any ques ons you may have at any me. Respec ully, ec ul ly, Paul S. Howard Urban Forester/Planner phoward@burdi.com

3 Summary Report 01 Introduc on Harris County Flood Control District (HCFCD) has engaged Burdi Consultants, LLC to conduct a vegeta on survey along Buffalo Bayou in order to quan fy the extent of woody vegeta on within the proposed easment for an ongoing stream bank restora on project. Project parameters for the survey include loca on and characteriza on of all woody vegeta on greater than eight inches in diameter as determined at breast height (DBH 4.5 ). Also included in the survey are all dead trees with a DBH of sixteen inches. The project area includes inventory of vegeta on within a twenty foot buffer outside of the proposed easement. Methodology The vegeta on survey was conducted by naviga ng throughout the project area using mapping grade GNSS (Global Naviga on Satellite Systems receivers (GPS)) to iden fy the limits of the project area and mark vegeta on loca ons. The GNSS receivers are capable of sub-foot horizontal accuracy (x,y axis) and sub-meter ver cal accuracy (z axis) under ideal condi ons. The GNSS receivers were configured for real- me differen al correc on using a satellite based augmenta on system (SBAS) to improve accuracy and loca ons were post-processed in the office using diffen al correc on data from local base sta ons within a 10 kilometer distance from the project area. Due to mul -path error (tree canopy, topography, etc) and satellite geometry; accuracy varied throughout the survey with the following accuracy sta s cs reported a er post-processing: Data Collec on All woody plants with a DBH of 8 or greater were located by GPS and the following a ributes were recorded: Species DBH Height Crown Spread Condi on Comments Plant communi es were iden fied and their boundaries mapped. All iden fied species of woody and herbaceous vegeta on were recorded along with general stand characteris cs to obtain an overall vegeta ve biodiversity baseline. Notable wildlife species and habitat were recorded as found. Digital photos were taken throughout the project are to exemplify par cular plant communi es, erosion areas, and other notable characteris cs. Photos include la tude and longitude coordinates recorded in the exif headers (geotagged) for integra on with GIS so ware. A total of 972 trees were inventoried within the project area in accordance with the survey parameters. The most common species inventoried were Boxelder (Acer negundo), Sycamore (Platanus occidentalis), American Elm (Ulmus americana) and Cherry Laurel (Prunus caroliniana). The species comprise the dominant canopy along the bayou with smaller representa ves in the understory. Cherry Laurel in smaller sizes is found in significant numbers througout the understory and is considered the most dominant species in that height layer. Tree condi ons were found to be in FAIR condi on (50.31%) and GOOD condi on (22.94%), with lesser numbers found in POOR (19.03%) or DEAD (7.51%) condi on. Two trees were found to be in EXCELLENT condi on, along with a few specimen trees usually located in maintained areas.

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5 Summary Report 03 General Bank Condi ons Observa ons were made as to the general condi on of the land within the project area. The land is composed of deep sands with varyied slopes throughout. Steep slopes are found throughout the project area with par cularly steep areas on the east end of the north side of the bayou and along much of the south side of the bayou. Erosion control and bank stabiliza on measures were noted in varied areas along the bayou including the use of pilings and concrete retaining walls (golf course). Tree roots are found exposed on most trees located on slopes or at the water s edge. Also noted is a significant amount of forest debris and trash deposited during flood events. Typical slope along bayou. Concrete retaining wall found along the banks adjacent to the River Oaks Golf Course Erosion has exposed the roots of most of the trees on slopes.

6 Summary Report 04 Invasive Species Non-na ve and invasive species were recorded as observed and as a component of the inventory of trees 8 DBH or greater. The most abundant species noted were Cherry Laurel (Prunus caroliniana), Waxleaf Ligustrum (Ligustrum spp.), Chinese Tallow (Sapium sebiferum) and Chinaberry (Melia azedarach). Chinese Privet (Ligustrum sinense) and Elephant s Ear (Colocasia esculenta) were also noted in small amounts sca ered throughout the project area. Generally speaking, the invasive and/or non-na ve species were found widely sca ered with no par cular pa ern of distribu on. Cherry Laurel, although na ve to the region, is o en considered invasive due to its ability to profilerate successfully and take over as the dominant species. Cherry Laurels along the north side of the Bayou within Memorial Park were found to have been treated for eradica on through the use of the hack-and-squirt method of herbicide treatment. A single brake of Giant Cane (Arundo donax) was located during the inventory. This species is considered invasive and should be eradicated. Elephant s Ear found in along banks has likely escaped from maintained landscapes Cherry Laurel treated with herbicide via the hack-and-squirt method. Erosion has exposed the roots of most of the trees on slopes.

7 Summary Report 05 Plant Communi es The species distribu on of vegeta on within the project area is rela vely uniform. Areas were Iden fied where disturbance has created open areas for young tree seedlings, herbaceous vegeta on and shrub species to develop. Most of the project area is comprised of mature stands of Sycamore, Boxelder, American Elm and Cherry Laurel with sca ered other species throughout. Ground covers are mostly limited to vine species and sca ered sedges and forbes as sunlight is limited in heavy forest canopy. Flood events have deposited significant debris in many areas, as well as washed away other areas on a regular basis. The included map atlas delineates the general plant communi es iden fied during the inventory. Young Boxelder growth in low-lying, frequently disturbed area. Maintained area at the Hogg Bird Sanctuary. Young plan ngs are mixed with the mature Sycamores, Boxelders and Elms. Typical understory of vines, Cherry Laurel and herbaceous vegeta on with varied slopes.

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14 Summary Report 12 Inventoried Species Burdi Consultants - Summary Report - Memorial Park Demonstra on Project Vegeta on Survey December 16, 2013

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