Winterberry

Written by charlie   
Wednesday, 29 October 2014 11:43

The hardy, deciduous shrub, Winterberry (Ilex verticillata) is a species of Holly native to the US, found East of the Mississippi ranging from Alabama to southern Canada, in swamps, wet woods and other areas with evenly moist, acidic soil.  Ranging in size from 8 to 12 feet in width and height, the Winterberry is also used in gardens as a cheery winter ornamental, thriving both in rain gardens and dryer soils, hence its Facilitative Wetland designation of "Usually occur in wetlands, but may occur in non-wetlands".   Winterberry propagates both by suckering and flowering.  As with the Spicebush, at least one male plant must be planted within pollination distance to females for them to bear fruit. Unlike the evergreen Holly, the Winterberry's leaves turn black at first frost and entirely loses it leaves -making its clusters of red berries even more striking on bare branches in the early winter.

Beyond its utility as an important source of food for nearly 50 species of birds and small mammals, its berries and branches are also used for fall wreathes and flower arrangements.  In the Berkshires, Massachusetts garden centers sell a small bouquet of  Winterberry for $7 - a well filled 5 gallon bucket is around $30  - you can even pick your own.

Visit the gallery page at the Lady Bird Johnson Wildflower Center for some great photos of the plant and berries.

Sources and Further Reading:

http://plants.usda.gov/core/profile?symbol=ilve

http://pss.uvm.edu/ppp/articles/winberry.htm

 

http://www.wildflower.org/plants/result.php?id_plant=ILVE

 
 

Amazon AWS and GDAL

Written by charlie   
Monday, 27 October 2014 02:14

The Geospatial Data Abstraction Library or GDAL, (http://www.gdal.org/) is the trusty, open source, Swiss army knife of geoprecessing software, providing behind the scenes muscle to many GIS programs, Grass GIS, QGIS and Geoserver included.

Wanting to merge 9 raster maps using gdal_merge.pyto model a watershed, I realized it was not natively available in Grass GIS. Having both a production server running Geoserver and content with my Grass GIS setup on my laptop - I was hesitant to install GDAL on either platform, it has a reputation for being difficult to install, and lacking the confidence to repair any dependency errors - I had two options.

I could have either pulled an oldlaptop out of storage and do a fresh Ubuntu install, orstart a Small (T1) Ubuntu instance through Amazon AWS (aws.amazon.com), install GDALand start and stop the instance it as needed. Taking the AWS route, it took less effort and time than expected. As an added bonus, the instance can beexpanded asneeded to process large datasets - try that with a clunker laptop running 2GB of memory.

Through the AWS Admin panel, I createda Small (T1) Ubuntu Trusty- 14.04 instance. Installing GDAL was painless, for my needs, it required both the GDAL installation plus Python, installed by using apt-get as follows:

sudo apt-get install libgdal-dev

sudo apt-get install python-gdal

Verify that gdal is installed and version by using:

gdal-config –version

After uploading and changing permissions of the files I needed to merge with gdal_merge.py, I ran the script, using thistimesaving tip, which will merge merge all files in the current directory with the .tif extension, as follows:

gdal_merge.py -o output.tif $(ls *.tif)

It took all of 30 seconds to merge all 9 files, and after processing the file was downloaded and worked correctly.

Additional Reading and Resources

Manual page forgdal_merge:http://www.gdal.org/gdal_merge.html

Manual page forgdal-config: http://www.gdal.org/gdal-config.html

http://www.sarasafavi.com/installing-gdalogr-on-ubuntu.html

https://gis.stackexchange.com/questions/116740/gdal-merge-py-on-ubuntu-many-tif-tiles-into-one/116770#116770

http://skipperkongen.dk/2012/02/21/pointers-for-gdal-and-python/

 

https://gis.stackexchange.com/questions/116740/gdal-merge-py-on-ubuntu-many-tif-tiles-into-one/116770#116770

Last Updated on Wednesday, 29 October 2014 11:55
 

Japanese Knotweed

Written by charlie   
Friday, 17 October 2014 19:35
Japanese Knotweed, never the prettiest plant either by reputation or looks, has been more noticeable the past few weeks on the margins of  I-95 and local roads, having just finished flowering. It has been identified as being an invasive pest for over 100 years, I recall it alongside streams as a kid, and thinking it was bamboo. My friends and I would run through  knotweed thickets and use the stems as swords and spears. Today its much more widespread -  and just as pernicious.  Fortunately for small blessing, since there are only female Japanese knotweed plants, the presence of flowers doesn't mean its reproducing since there is no fertilization via pollen. This is certainly not to say that Japanese knotweed cannot colonize new areas, it  spreads quite readily via cuttings and rhizomes.  A piece of root the size of a dime is enough create a new plant, and begin colonizing a susceptible area.
In the UK, it  endemic and has been much more visible battle, to the point that any soil with knotweed roots is considered contaminated, and must be disposed of properly.  Yes, it is that pernicious.  There is now a requirement during the mortgage process that the owner has to certify that the property is either knotweed free or it is being actively treated.
The best practice for eradication is spray, cut and repeat annually.   The process must be repeated for 5 years to be declared knotweed free.   Why is it  so difficult to get rid of?  One answer - its rhizomes, or roots.  The roots, a large misshapen mass, stretch for  yards in every direction, sits underneath the stems as a source of energy, and has enough strength to push its shoots through any crack.  If the foliage and stems are removed, the plant has enough energy stored in its roots to push up additional stems, again and again.  Once the stems are through the soil, photosyntheisis takes over and the energy that was expended by the roots to push up the stems, can now be replenished easily due to its fast growth.
Sources and Further Reading:
http://www.invasivespeciesinfo.gov/plants/knotweed.shtml
http://wiki.bugwood.org/Archive:BCIPEUS/Japanese_Knotweed
 
 
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