City Trees is a premier publication focused on urban + community forestry. In each issue, you’ll learn how to best manage the trees in your community and more!
Issue link: https://read.dmtmag.com/i/346592
ÜÜÜ°ÕÀL>vÀiÃÌÀÞ°V CROSSES 4HE WHITE OAK GROUP INCLUDES WHITE OAKS BUR OAKS SWAMP WHITE OAKS CHINKAPIN OAKS AND MANY OTH ERS h7E ENDED UP WITH UNIQUE GENOTYPES FROM THE ACORNS THAT RESULTED FROM THESE CROSSESv "ASSUK SAYS h/F THOSE OF THEM PROVED THAT THEY CAN STAY GREEN AT A VERY HIGH P( 4HE OTHER ONES DONT LIKE HIGH P( BUT ARE GOOD FOR EXCEPTIONAL FORM AND OTHER ORNAMENTAL CHARACTERISTICSv .OW THE TASK OF THE RESEARCHERS IS TO FASTTRACK PROPA GATION OF THOSE MOST PROMISING GENOTYPES h2IGHT NOW WE ONLY GET FIVE OR SIX NEW PLANTS A YEAR FROM EACH STOCK PLANT AND THAT REPRESENTS A BOTTLENECKv "ASSUK SAYS 3HE AND HER RESEARCH TEAM ARE EXPLORING HOW TO GET MORE ROOTED SHOOTS PER PLANT IN AT LEAST TWO WAYS 4HEY ARE APPLYING THE PLANT HORMONE GIBBERELLIC ACID TO STIMULATE MORE BUDS TO BREAK AND THEY ARE USING BOTH GREENHOUSE AND FIELD PRODUCTION IN ORDER TO GET TWO FLUSHES OF NEW SHOOTS PER SEASON RATHER THAN ONE /NCE THE 5() TEAM CLEARS THE PROPAGATION HURDLES NEW OAK HYBRIDS WILL BECOME COMMERCIALLY AVAILABLE 5RBAN FORESTERS SHOULD BE ON THE LOOKOUT FOR THIS SERIES ONE THAT WILL MEAN THE END OF THE VEXING IRON CHLOROSIS THAT CAUSES OAK LEAVES TO TURN YELLOW .O LONGER WILL ARBOR ISTS HAVE TO TO TREAT IRON CHLOROSIS WITH SULFUR AND IRON CHELATION TREATMENTS 4HE "UBBLES &ACTOR ! SECOND 5() RESEARCH PROJECT SEEKS TO ANSWER THE QUES TION h7HY ARE SOME SPECIES SO MUCH MORE DIFFICULT TO TRANSPLANT THAN OTHERSv !RBORISTS KNOW FROM THEIR OWN OBSERVATIONS THAT HONEYLOCUSTS ARE A PIECE OF CAKE BUT THAT MOST TREES IN THE OAK FAMILY ARE DIFFICULT TO TRANSPLANT 2ESEARCHERS HAVE LONG SUSPECTED THAT CERTAIN TREE SPECIES ARE MORE AFFECTED THAN OTHERS BY THE WATER STRESS INHERENT TO TRANSPLANTING "UT WHY "ASSUK POSITED THAT THE REASON SOME TREES BECAME MORE WATER STRESSED WAS BECAUSE THEY VARY IN THE EXTENT OF THE FORMA TION OF AIR BUBBLES IN THE XYLEM THE WATERCONDUCTING TISSUES OF THE PLANT 4HIS PHENOMENON KNOWN AS CAVITATION IS ANALOGOUS TO A BUBBLE IN A DRINKING STRAW THAT MAKES IT HARDER TO SUCK UP THE LIQUID 5() ACQUIRED A HYDRAULIC CONDUCTIV ITY METER THAT COULD MEASURE PRE CISELY HOW MUCH WATER RESISTANCE AS A FUNCTION OF CAVITATION IS PRES ENT IN PLANT TISSUES 4HEY DESIGNED AN EXPERIMENT TO TEST TWO SPECIES THAT EVEN THOUGH THEY ARE RELATED ARE OPPOSITE IN THEIR TRANSPLANTING EASESWAMP WHITE OAK BLISSFULLY EASY AND BUR OAK NOTORIOUSLY DIFFICULT 4HEY TESTED TWOYEAROLD SEED LINGS ON UP TO INCH MM CALIPER TREES 1ÊÀiÃi>ÀViÀÃÊ>ÀiÊ>ÌÌi«Ì}ÊÌÊv>ÃÌÌÀ>VÊ«À«>}>ÌÊvÊ>>iÌiÀ>ÌÊ>ÃÊÌ>ÌÊ ÃÕ`ÊViÊÌÊÌiÊ>ÀiÌÊÊÌiÊiÝÌÊvÛiÊÌÊÌiÊÞi>ÀÃ°Ê /iÊÀÌÃÊvÊÃÜ>«ÊÜÌiÊ>]ÊÜÃiÊÝÞiÊÃÊiÃÃÊ}À>ÛiÞÊ>vviVÌ i`ÊLÞÊV>ÛÌ>ÌÊÌ>ÊÌiÊÝÞiÊvÊLÕÀÊ>°ÊÊÊ