01-31-85 Agenda & Packet - Laserfiche WebLink

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_ _ _- �_ 1981 FORL�STRY PRO(:RAM SIIMMARY �"� W7CH F.LM DISEAFE• OAR WILT AND HA2ARbbUS iRRE RF.MOVALS The year 19A4 was one of increases in bnt� Dutch elm disease and oak x+ilt. Dead and Aying etms removed numbered one hun- Ared twenty (120); forty (40) or 33 percent, were Chinese or Siberian elms. Twenty-two 122) woodpiles were found to con- tain elm or diseased red oak wood and promptly removed. The annual elm loss rate increased from last year's .7(1 per- cent to 1.36 percent. This is near.ly a two-fold increase in elm removals. Most municipalities saw a comparable rate of increase. Resea[Chers have pointed to better win[er survival (�eavy snow conditionsl by the elm bark beetles as a pcincipal reason for the increases. Additionally, a possible mutation of the disease itself is being studied. Non-diseased trees removed Erom parks and boulevards numbereA six. Foremost among these trees was a 41" diameter cottonwood removed from Silver View Park. Trenching as a means of oak wilt control was not utilized in Mounds View in 1984 for reasons of inechanical breakdown and lack of crew (autumn). NORWAY MAPLE WINTER KSLf. Extreme weather conditions in the fall and early winter of 1983 leA to serious death and dieback in many of the Ci[y's Nocway maple and w�ite ash varieties. Bspecially hard �i[ were the newly plaoted trees in parks and public areas. Eighty-four (84) of these trees were removed from City packs. Nhat could be termed a lack of "hardiness" was generally responsible for the damage. An unusually mild fall, coupled with a early and severe winter did not allow t�e trees proper preparation Eor dormancy. The result was tne death of the trees "living" combium layer, lack of nutrient and water translocation anA a visible cracking �r sl��ughiny of the tree's bark. Often t�ese visible symptoms, especially in [ne case of partial damage, were not evident until grow[h had com- menced in t�e spring. Partially dameyed trees, thouyh snme- w�at disfigured, �atl healthy foliaye, come oE these witl recover in due time; others wi I1 start a slow cycle of de- cline. T[ees on private pcoperty displayed the same inciAence of dam- age wit� most older trees surviving and most younger trees 9eVeCly damaged o[ Aead. All [otalleAr one hunAred tvelve (112)treea vere removed from parks hecauac nf tne ahove men- tioned damage, va�dalism and root failure. ��