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: http://read.dmtmag.com/i/417159
ÌÞÊ/Àiià À>>}iÊÃÞÃÌiÃÊÃÕ`ÊLiÊVÃ`iÀi`Ê>ÃÊiÊ«ÌÊvÀÊ«ÀiÛiÌ }Ê«À}i`Êv`}Ê`>>}iÊÌÊÌÀiiÃ°Ê #ONSEQUENTLY MICROORGANISMS ADAPTED TO LOW OXYGEN LEVELS PROLIFERATE IN THEIR PLACEEG 0ARACOCCUS DENI TRIFICANS SPECIALIZED SPECIES OF #LOSTRIDIUM 'EOBACTER 0SEUDOMONAS AND $ESULFOBACTER 3UCH MICROORGAN ISMS ARE ASSOCIATED WITH THE PRODUCTION OF SUBSTANCES TOXIC TO THE TREE ETHYLENE AMMONIUM REDUCED IRON AND MANGANESE SULPHIDE RELEASE OF NITROGEN FROM SOIL AND SOIL ACIDIFICATION %XCESS WATER ALSO DILUTES AND MOVES PLANTAVAILABLE NITROGEN AND OTHER NUTRIENTS AWAY FROM THE ROOT SYSTEM 4REE ROOTS CAN SURVIVE WITHOUT OXYGEN FOR A LIMITED TIME BUT NOT FOR PROLONGED PERIODS 0ROLONGED WATERLOGGING INFLUENCES ROOT METABOLISM RESULTING IN THE BUILDUP OF TOXIC METABOLITES WITHIN ROOT TISSUE WHICH ACCUMULATE AND DAMAGE THE ROOT CELLS 2OOT DAMAGE DURING WATER LOGGING IS INDICATED BY BLUEBLACK DISCOLOURATION AND PEELING BARK 2OOT TIPS AND FINE ROOTS WHICH ARE CRITICAL PARTS OF THE ROOT SYSTEM FOR GROWTH AND NUTRIENT UPTAKE ARE ESPECIALLY AT RISK 7ATERLOGGING PREVENTS NORMAL ROOT FUNCTION AND THERE FORE DETRIMENTALLY IMPACTS ON TOTAL TREE BIOLOGY $UE TO STOMATAL CLOSURE PHOTOSYNTHESIS IS INTERRUPTED HAVING TWO MAJOR IMPACTS /NE THE TREE IS UNABLE TO PRODUCE SUFFICIENT CARBOHYDRATES FOR GROWTH AND SO RELIES HEAVILY ON CARBOHYDRATE RESERVES 4HESE RESERVES ARE FOUND IN THE ROOT SYSTEM AND SO BECOME AT RISK OF DEPLETION 4HE LONGER FLOODING PERSISTS THE GREATER THE RESERVES EXHAUSTED 4WO INHIBITED PHO TOSYNTHESIS PRODUCES BYPRODUCTS SUCH AS HYDROGEN PEROXIDE AND REACTIVE OXYGEN SPECIES WHICH DAMAGE ESSENTIAL CHLOROPLASTS AND PLANT CELLS 3YMPTOMS ARE SHOWN IN THE CANOPY OF THE TREE AS LEAF YELLOWING AND SENESCENCE REDUCED FRUIT YIELD WILTING SHOOT DIEBACK AND DECAY 4REES DO HAVE SOME ADAPTATIONS TO LONGTERM WATER LOGGING SUCH AS PRODUCING ADVENTITIOUS ROOTS ABOVE THE WATER LINE AND TRANSPORTING AIR FROM ABOVE GROUND THROUGH THEIR TISSUES TO THE ROOTS (OWEVER TOLERANCE TO WATERLOGGING AND THE DEGREE OF USE OF SUCH ADAPTA TIONS VARIES MARKEDLY BY SPECIES %XAMPLES OF TREES WHICH OFTEN FORM ADVENTITIOUS ROOTS ARE SILVER BIRCH "ETULA PENDULA COMMON ALDER !LNUS GLUTINOSA GIANT REDWOOD 3EQUOIA SEMPERVIRENS AND WILLOWS 3ALIX SPP !LONG WITH TREE SPECIES PLANT AGE AS WELL AS THE MOVEMENT AND PROPERTIES OF THE FLOOD WATER ARE IMPORTANT FACTORS IN WATERLOGGING SURVIVAL 4REES VARY IN WATERLOGGING TOLERANCE BETWEEN CLOSELY RELATED SPE CIES AND EVEN WITHIN SPECIES )N GENERAL BROADLEAVED SPECIES ARE MORE TOLERANT THAN CONIFEROUS SPECIES 4HE SEASON IN WHICH FLOODING OCCURS ALSO HAS AN IMPACT DORMANT TREES SHOW GREATER RESISTANCE TO SHORTTERM FLOODING 4HE SPEED AT WHICH THE GROUND BECOMES SATURATED IS ALSO IMPORTANT AS SLOWER WATER LOGGING ALLOWS THE TREE TO ADAPT TO SOME DEGREE $ISEASES $AMAGE TO ROOTS FROM WATERLOGGING STRESS LEAVES