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HomeMy WebLinkAboutResolution 90-407 12/10/1990Resolution No. 90-4(17 1\I.C.s. of the City of Petaluma, California RESOLUTION ACCEPTING THE OAK HILL PARK TREE EVALUATION CONDUCTED BY ARBORIST, ROB GROSS, AND AUTHORIZE STAFF TO TAKE CORRECTIVE ACTION. Whereas, the City Council at their meeting of March 19, 1990, authorized staff to contract with Arborist, Rob Gross to evaluate the oak trees at Oak Hill Park; and Whereas, Arborist, Rob Gross, has completed the evaluation of oak trees at Oak Hill Park and found a number of conditions which adversely impact the oak trees at the park; and Whereas, Arborist, Rob Gross, recommends a course of action to remove hazardous trees, and corrective action for remaining trees at Oak Hill Park; NOW, THEREFORE, BE IT RESOLVED, That the City Council of the City of Petaluma, hereby accepts the report prepared by Arborist, Rob Gross, and directs staff to take the corrective measures recommended in order to improve Oak Hill Park. #21:resoaks Under the power and authority conferred upon this Council by the Charter of said City. REFERENCE: I hereby certify the foregoing Resolution was introduced and adopted by the Approved as to Council of the City of Petaluma at a (Regular) (,j~~~tX~~tte~ meeting fO~' on the ....l.~lt.h..-.-....... day of .............12e.cemb.e.~.......................-., 19...~.~, by the following vote: City Att rney AYES: Balshaw, Sobel, Davis, Woolsey, Vice Mayor Cavanagh, Mayor Hilligoss NOES: 0 ., ._. ABSENT: enter - ~ i '" ' ,% ATTES'T' : .................... ..:- .. ... .......-- .. ..... .. ......-...'... ity Clerk Mayor ~ Council File..._ ..............••-----.-.-...-.. CA 10.85 Res. No.....9.Q.~.~F.Q.7........ N.C.S. 7.August 1990 • ~ PREPARED`.FCfl: The City of Petafuma, Parks bepartment . and Oak Hill Park Citizens Advisory Committee PREPARED BY: Rob Gross . ®@II~dPOT@C,h The: Tree Technology Com a~nv, PO Box 766 Calistoga, 'CA ' .54515~ - (707) ' 578' - 7199 TABLE OF' CON'T`ENTS . :..Executive Summazy...:.... ~ ........... .......::......... 1 Methods of Study ............. , .......................... 2 Site Description ........ ............................... 3 Location Map ................. ... ....... ............. 4 Site Map... .... :... .......... ..... _ ... ..........` 5 Figures.....: .. ..~ .,....... ...... .... ... ... 6 Definitions................ .. ... .................... 9 Inventory.....:.,..... .. ................ ............. 11 Discussion. ............................ ...... .... 19 Conclusions/Reeomendations ................... ......... 21 -Natural History of Oaks Growing at, this Park..... ............. 23 Select. References ~ : ... ........ ............. ...... .... 24 'Appendix e - ~ ~ L,IS'I' .OF FIGLJR~ES F 1 Upper"Oak, Hill Park. Irrigated turf,. ,hard surface and Coast; LiveOak #78 over the~children's play area. -~ ~ - 2 Lower Qak, Hill, Park looking :toward,'.Park View-Terrace. not irrigated. , grasses cut; so~arees in rows. ~ ~ . 3 Leaning Coast,Lye Oaks . #. 69 basal cavi y filled with cement. - roots lifting soil on uphill sides foliage presses:against tree ,# 70. . 4_' Cupped foliage on Black Oak :#' 29 ~ - - 5 Ganoderma~ oregonense fruiting on the.~ha"se>of'leaning Coast- Live Oak # 68. 6 'Thin folage~of Coast"Li've;.Oak # 75. 7 Oak Root Fungus `killed: 70% of Root Crown on Coast Live Oak #' 70. ~x~cu~~ s~A~~r . Oak Hill. Park,~s a 5,2 acre neighborhood park. The. vegetation is dominated by .. over 88~ Large trees of~•whieh 81y are oaks," one is ~a!Monterey cypress and. ix are Monterey pine. The park" is divided -into two "distinctly different; parts, the upper park,area and the lower-park area. The upper. park area is irrigated. arid.is covered "by turf. The .lower area 'is not' irrigated :and. the summer dry grasses:' and fortis, are left as cut stubble. Very."few oak seedlings" or sapl'ings`exisfiin the park. Many of the ofd trees are failing in health and/gr-atructure. Nine trees .are recommended "for removal immediately and .most- others need some.. attention;. This population. is dominafed.`by large trees with. very #ew :young replacements. Root diseases are :debilitating the "oaks in the irrigated 'upper ,area. Wood decays are reducing the structural integrity of the trees, in the dry lower area. ;Structural problems are exacerbated'by"trees"wlich lean or are imbalaneed. Oaks are well: adapted to qur 'Mediterranean climate with dry summers. Warm eason ;irrigation is both unnatural and .problemati'c `for ,`our native oaks. Root diseases associated with warm .season irrigation are a major factor leading to "loss of native oaks.. If "the irrigation ,s~ topped, the .environment will be! more - hospitabl'e for,; the trees ~arid less hospitable -for :.the fungi and the trees. often respond favorably. Loss of roots and barkweakens oaks and allow exposed tissues todecay. " Once a tree is"decayed the structural. weakness can not be reversed.,or healed. A detailed inventory provides tree by tree insights and recommendations; and - establishes relative pr-iority for the, recommended work. Overall the hazardous "trees should be 'removed promptly.. The sprinklers should 'promptly be .adjusted ten feet away from the trunks 'and" "roof crowns (the ;critical area). The problems-tic :irrigation" should be "dscontinu'ed, this fall. ,'and ~fertlizer should ~'be applied .in September. Landscape plans should be developed with understanding of. tand. conditions aril oak :needs. Special attention should be given to avoiding target .areas. Turf should be shifted to areas~without:"oaks such as the two-dirt parking~areas and the . blocked, roa. dway. 'g'I~O~DS ®F S'TLTI3~l 2 The .Oak Hill, Park-trees and, various environmental factors were observed and nofes. were recorded on several occasions." ~ Considerable help was provided by Oalc Hill. Park Citizens' Advisory Committee . In particular,. Dave Webster helped at`.aength on mapping; suraey and review, Walt Mahoney .provided field assistance and guidance for the project and Larry Reed developed the site map and other graphics. All, trees two and one' half ,(2:5) inches' in diameter or larger are noted on the site map and in the `inventory, Each tree is ,tagged on the north.sde at seven feet -above .grade with a softaluminum tag which, is attached to the trunks with an aluminum nail. Diamete"r" pis Measured at four and: one half feet above the grade. The: dripline is measured by ,pacing four separate -radii.. Thee Root Protection Zone is calculated. by "multiplying `thee widest radius times three or the dripline plus radius. All .observati'ons were made ;from the ground. Tree environment; ~ structure, vigor; target (direction of lean .or :imbalance), observed defects,: pests; visible signs .and symptoms; roots, trunk, limbs,, foliage and :horticultural' practices are~noted'where. appropriate. These data are synthesized, recommendations .and priorities: are provided. -The: soil description :is from the. SOIL SLPRVEY.,: 'Sonoma County, California . issued May 1972 .by- USDA, ForestService and Soil Conservation Service with. UC Agriculture Experiment Station: ~ Weather data is :'from Climatological Data of California, published by National Oceanic' and Atmospheric Administration: Soil-and root .samples were dug from four separate loeati`ons and later combined: and. bagged in '.Zip-Lock''bags :and. shipped to the respective :laboratory by #irst ,class US mail. Root and~soil samples were analyzed' for nematodes and; disease. Foliage samples were: bagged and shipped the same way. Foliage was inspected for ;mites and, insects and analyses for-a chemical "fingerprint" (in progress) for: suspected. herbicide. damage, Trees were visually inspected, sound tested with a hammer and tissue sampled with a :roofing hatchet, chisel or small trenching. tool. No root'crowns were excavated: Water use was calculated~by Wa1t~ Mahoney, .Historic- inforInafion- wasr provided . by Ed Manion of the' Petalirna .Historical Museum. i . P _ ~~ ~S'I'I'E I~:ESCRII?'TION 3 ,, . ~. This ridge top park is ~ about one half' mile west` of central°Petaluma and covers 5:2` acres. The upper third is, relatively flat, has over..21 trees and,lis irr_.gated. It has _ __ ~ tables, barbecues; ~a basketballs court, ;a ~chdren's_ play area with swings, other .,, equipment and. rest rooms... To :maintain the tur€, ~ the upper area is irrigated. and' mowed regularly. The northern, _twa thirds (the' lower ~area~) has over ~~34 trees; some planted in; rows. (seep Figure 2 );~~and is :note irrigated 'and there also :are benches, tables and barbecues. The grasses,, forb"s and small woody plants in Phis area are cut at, leasf once~:each'year. Terrain slopes down into a-bowl from the . two dirt parking areas ntor the'lower. ~ dry area. ~~ The: vegetation is dominated `by large coast live. oak; .black oak and valley oak. ` trees. At. Oak, Hill Park there are over. 88 trees, at' leash two and one half (>2:5) inches. ~.in Diameter at Breast Height(DBH). Eight trees'~;have doublestems; two trees have four. stems and all the, rest are single stemmed. Fifty five are ,large. Coast Live Oaks: with 21 specimens hamming: a DBH of 15~;to X30 inches. Nineteen. are black oaks with T5~ trees larger' than 15 inch DBH. Seventeen are valley oaks. _ The one Monterey cypress~s, over fourfeet in diameter: ~ There is a fence row of ,~ various exotic shrubs; oak seedlings and vines along the fence by Park. View ' Ter-race. ' The local.. climate is' :characterized by moderate temperatures and seasonal _ ~ ,precipitation.. One hundred and ten.and 1`9 degrees.F:are,the extreme temperatures,;on..record. The mean annual temperature is 57:7 degrees. . ~ Summers are dry and warm to hot, with strong.. marine fog and._ coastal influence. Winters are cool and wet;. 'providing an average of 24:1 inches. of rain annually. Soil s~~;described as Cotati fi~ne.sandy~loam which-`has a high erosion hazard; 4 =5 _ ~ ~ fire inches of water holding capacity, and is poorly drained. in parts below 20 - 24 inches: - ~ 4 - zA .. t. _ • _ - - 12 ~1Nr1 ~ ' 8001 .. 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"Upper Oak HiIY Park. ~IrrigaEed, turf, pavement and a children's~play area, •with CL # 78 above: Figure 2. Lower Oak Hill Park. Looking toward.,Park View Terrace. ~[Vot` .irrigated; grasses'cut, some areas in rows. • ~ . Figure 3. ;Leaning Coast Liye ~aksr #; 69 basal cavity filled with cement (and cracked); roofs, liftingEsoil on iphill side., foliage leans on #70. #69 sans; roots lifting soil and Ganoderina oregonerise fungus is fruiting base: Figure 4. ,Cupped foliage on Black Oak #29. . r 8' . Figure 5.. ~anoderma oregenense frtiiting ;gin the ~+ase of Loast Live Oak # ~. Figure 5. Thin fotiage of Coast Live, (7ak~75: figure 7. -Oak Root Fungus killed'7[~%=of Root Crci~vn on Cciast Live Oak X70. Aeration -Processes wheh'increase^soil aeration, .usually-to 36 inches depth in the;entire IZI'Z: ' , 1) Vertical Mulch, .drilling holes'2 'ir-ehes diameter 2) Hydrojef bores holes 3' feet deep' in the soil with high pressure water' Base:-The base of the_tree trtunk,; "for the purpose of this report. ' • ' Buried'-Bazk - An un3esirableanatomcalfeature at.the~union',of,onebranch'to another or~the main. stem where the crotchjoins at.;an~acute angel<and the'bark~'emanatesim a fissure actually separating parts .of.~ the two structural uruts.~ • Canker - A.dead, usually~depressed portion of bark.. DBH. =Diameter at Breast `Height Exclude -Keeping out:people~and pets; ;usually for~safety reasons where tree structure is compromi`s".ed creating,a `hazardousrsituation„" for.'the duration of~a project. The materials `are`- commonly pounded "T" _posts, °wire,or plastic.fencing rriaterial "completely encircling he tree at the outer edge ofsthe RPZ: ~ . . ~ - Imbalance -Lack of balance of the tree canopy, due to foliage distribution; branch~distributiom, competition for light, etc ~ ~ ~ ~' N/A -.Not Apphcable;,or':Not:Available, Organ ~ ., is Mulch = Anynatural,bulky material, ;such as treetclups;, which are suitable to. enhance the soil physical' and biological- conditions. Tree: etups,,~-`Nitrogen~fertilized, moistened and mulched ..until:eool(about~two.weeks if turned or otherwise"aerated). 1tCE - Root.Ciown;Excayation is the process qf-removing soilfrom;around the root crown., "Conditions. are ':then appraisea;by examination for disease invol~emenf'and structural defects. RCE provides the .following advantages: ' 1) Exposes ~origirial ,grade `level 2") ~ Access stnctural defects and-disease '~ " .: ~_ . ' ~ 3) 'Inhibits root,and buttrot fungi'. ' . . Root Protection.Zone (RPZ) :The°area lielow,andrsurroundng the,•ree canopy,. Tlus is a' means' of "establ`shing he root area of `trees Most negate"ve disturbances in the ~ItPZ will. alsohave a deletenous~ effect. on ;the aerial' pgrtions of `the tree later. The ItPZ; is determined by either of 'the following ;formulas: ®For`leaning, trees- Widest radiuatimes 3 ~ . ® For upright and balanced izees - Dripline;pltis 50% or dripline plus radius. Target`- The point or aea where a tree or any of its, parts will most likely land upon failure. Temporary Protective Fencing - A fence which is :intended; to exclude ate human. activities in the. ItPZ for the.duiaHon o'f'a project, season, incident, e'tet; t 10 . Tree Species:: V -Valley oak, .Quercus. lo6atq ~ , C•L -Coast:L~~e Oak, ;Q; agiifoln; B -Black Qak, Q, kelloggi' • , MP - Monterey-fine, Pinus radiata 1VIC -Monterey Cypress, Cupressus macrocarpa Prtuung Standards -Western Chapter,. International Society of.Arboriculture, T988 .. ~ . Crown Cleaning(CC) -removes" dead, dying, diseased, crowded, weakly attached; .arid low-vigor branches and water sprouts from a tree crown. Crown'Thinning =Selective removal. of mostly side branches. ' Crown Reduction -•Thinning cuts to reduce"height or spread of canopy. Crown Restoration - Pruning'to improve•the structure and appearance; especially after topping and other excessive trimming. Crown Raising;-Removal of lower branches for`ncreased clearance. Cable:- A flexible cable support sysfein,for'struc'turally compromised trees. Priorifies• URGENT is the most pressing,priority . ~ ~ Y = High-priority,. ,take a"coon within one year ,.". °' ~ ~2 _, Intermediate pnorty, take action within two years. 3 =Low priority N/A =Not Applieable'.or IVot Available . 4 11 ' - ~NVENT'ORY. ~: # SP' .. DBH.: Conditions. Recommendations and Priority 1 V .20.9, 13.4 Basal cavity; soil mounded ®base - Root Crown Excavation :(RCE), Crown. Cleaning- {CC): 2 ` 2 CL 30.7 Lean.targetssidewalk; stubbed over sidewalk, dead bark at base, seedlings below RCE, Crown Thinning, Protect seedlings: 2 • 3 CL 16:6 - Imbalanced ' CC, Crown Reduction of 6 inch diameter limb over ~adewalk, RCEb.1 4 CL 23:7 Lean targeEs'trail, dead bark and exposed wood at bases ' woodpecker holes - Remover 1 5 V ~ ,35.7 Read bark ®base; .seedlings-below; foliage thin RCE, CC: 2 6 CL 31.4 Lean targets Park Side Terrace CC, Crown Reduction for balance: 2 9 V 29'.2 - Basal wound from aractor CC: 2 8 V ~ 21.8 Among cherry plums, deadwood to 4 inches diameter •' RCE, CC: 2 9 B 35:6 ~ Pavement in 509+01tPZ, imbalanced, decay®6, '18 + 20 ft CC, Crown Thinning Southern limb,. Cable: 1 '` 10: CL 26S _ ~ Wound: ®%base.2 inch x 6 inch, Carpenterworm in limb on'South, , . 'rootcrown bleeding, bleeding lesions above 20 ft RCE, CC, ' :control Carpenterworms: 2 11 CL 33 . Imbalanced„ dead bark ~ base.+ ®Znd crotch, decay ®6 ft, deadwood: to 5 inches diameter RCE, CC, cable 2nd crotch: 2 1,2 CL 26.1 Bark missing'(3x) ®'base~(tractor), decay fo? lowest crotch, numerous dead twigs RCE, CC, Cable lowest limb: 2 ~ 12 :. 13 B 30.2 Imbalanced', dead barkand exposed wood at base, Poria species ' ~ ®'base, decay in 2large pruning,wounds . ReII10Ve:~. `l. T4 CL 245 Nocaction ®tFiis time ~~=15 Cti 18.2;. 16:6 Lean.;targets tree 16, buried bark in lowest crotch w/decay; woodpecker high use tree, cement seats below RCE, CG Crown ~Tlunning •and Crown Reduction of low horizontal limb to East, cable: 2 • 16 CL 18, 133` - Nice climbing, tree with good branch distribution CC: 2 • ~ 17 B 24 Small, over sidewalk, interesting hape CC: 2 18 .CL <25 Small tree near sidewalk ' • CC, 2 ' ~ ~ 19 CL 20;3, 78.T Crotch w/ buried bark, .dead bark + decay in patches fo l0 ft RCE, cable: 2 • 20. CL .16.8; 21, . Girdling root, crotch w/.buried bark ®4.#t, decay"~ 2nd crotch • RCE, cable. (3x), CC, remove girdling root:. 2 21 B 19.8 Dead bark ®base + to 6.ft, dead top, lean w/ decay on uphill side, Pit-scale - ' Remove dead top, . CC, retain. temporarily: 1 22 B 24:7 ' Exposed roots in trail, :decay ®:base to:7 ft, 3 ft long;crack ®18 ' ft w/decay deadwood to,3 inches diameter, when split is removed the tree will be.imbalanced " • 12 inch diameter limb to .North remove; retain temporarily and Grown Reduction of 'Southeast .limb; 1, 23 CL 20.8' Lean targets path, roots exposed w/ dead bazk,on uphill side ofr '' ~. lean, (neighboring trees'to; be:removed) ' `Remove. 7~ or .Crown, Reduction: 1 - 24 CL 39:5 Girdling-root, bleeding ®30 ft, deadwood to 4 :inch diameter - ~ CC,, In Tree Inspection (I'I'I) see :crotch. ®7 ft + ' cableTi: 2`. ' 25aMC 53:4 Disallow, use~of climbing hooks on this and all other living trees, see = Prunng~Standards WC; ISA 1988 No action ~; t1iiB Mime • ` ~ 25b CL: 21.7 -13 Limb over~sidewalk~ stubbed to' 6 inches diameter CC: ~ 2 26 B 21.7 Decay'®3•branch wounds, low limb torn away .. ~ Remove: .a . • 27 CL 11.4, 11; In parking area, . compacted soil, pleasing shape, stubbed re? light . . standard RCE,,. aerate: '1 28 CL 246 Compacted soil, imbedded .bark ®6 ft, decayed crotch ra110 ft ' Aerate, CC, remove limb to East W/ decay ®10 'ft; 2 29 B 241 Root Crown cankers, dead lesions on trunk ®crotch Remove: 1 • ' . 30 B 27:2 Cupped foliage (sample~beng analyzed for chemical - mntamination), wound ®1.5 - 3 ft, deadwood to 4 inches diameter - CC, monitor foliage conditions, seek' additional • attention if cupping persists in 1991: 2 31 CL 28:6 Compacted'soil; girdling root, wound;at base to 2 ft ,callus covered, embedded bark re? 6 ft Aerate, remove gtrdling'~ mot, CC: 2 0 32 B 26 Dead bark ®base:ao 2 ft, deadwood to 4 inches diameter, cupped foliage limited RCE, CC: 2 33 B 18.6 Bleeding'South side of'base, .deadwood to 5 inches, diameter RCE, CC: 2 34 CL 18:6 Deadwood to 1 inch diameter .. RCE: 2 35'. B 23.4, 192. Root Cmwn bleeding w% dead`bark + exposed wood, deadwood to 5. = inches diameter imbedded bark ®3 ft dead lesion to 7 ft ' .RCE; CC, ' cable, monitor lesions: 1 36 B 243 .Lean targets.trail, hollow. to 10 ft Remove:• URGENT 37 CL x_37:8 Lean targets-play area,: cavity2 x 4 ft re?'base from torn away limbs, hollow ~ • REMOVE or_:b;ace, CC, 6mwn restoration, re-orient play area to avoid target area: URGENT a 14 38' CL 28.8, '26.T Imbedded Bark°fe?;3 and^6: ft, thin foliage, single bench below • ~ - CC, RCE,; cable (2x): 2 39 B 21:1 Wounds + ecais below 6 ft, deadwood;to 8 inches diameter EtCE, C~C, monfor cavity: 2' . 40 CL 22.3 Leantargets tree °40, 'wounds alongarunk ko 10,;fE, thin foliage,. dead~bark;+`ezposed wood (5x)'to 6 ft, mots uphill compacted near . table;,Twig Blight - RCE, aerate; organic mulch, CC: 2 41 CL 335 ~ Lean targets open "area away.~from tables, embedded bark ~?l0 ft CC, Crown Reductiion of heavy tips, cable: 2 42~ CL 322 ~ . Base wounded by tractor on IVW side, lean targets table and. water fountain, ~ decay ®7 ft CC, Crown., Thinning: 1 43 CL 23 , . Lean targets opera area, repeated tractor wounds on uphill side of lean, decay ®:base.- 2ft, deadwood to. TO inches diameter. RCE, CC: 1 44 V 225 Imbalanced, 2 target :cankers, thin foliage CC, remove; 2 limbs w/ cankers, Crown Reduction for • balance; .RCE: 1' 45 V 22 Lean targets' Park`Side Terrace, decay a? 1 ft, deadwood to 6 inches diameter RCE: i . 46 CL N/A Lean targets,-open.;area, trunk covered w/ vines;. decay ®15 ft! - ~ ~ upper side of`lean • ' REMOVE or Excludes 1 ' ' 47 B 10.4, `9:7; 7.4 ._ Stump sprouts, 'stump rotted away ' ' - ATo ~actiom ~ this time ' 48 CL ' • ~-38 Lean targets.open area to East ~CC: ~2 . 49 ' CL . 244 • • . 'Decay ®base, bleeding ®3 ft ± above from Carpenterworm ITI of~ and' :'control CaTpenterworm, CC, RCE: 2 - 50 . CL 29:3' " Compacted soil, basal~cavity Aerate soil;,'CC, Crown reduction + Crown'Raising of. 10 inch. diameter, limb: over parking area: 2' . ;, 1 5 51 CL 25.2 . Imbalanced, 5096~:of bark is dead omlow side, deadwood;fo.5 inches"diameter • ~ 52 CL 221 - ' V1/ound'~ 8 ft'is 3:inehes~diameter, deadwood to 3 inches diameter . • . RCE, ,CCU 2 .. 53 CL _215, Basal wound;3 inches x 1 ft, lean targets; open.area.to East RCE; CC,• Cmwn `Raising-for vehicular clearance if ' roadway". ie to be retained: 2 54 CL :21:1 '' Compacted~soil, `RPZ 40~ .pavement, ;cavity ®base 16 inches diameter fron- missing trunk, lean targets. North • - RCE, aerate; organic mulch: 2 55 .~V 242 - Lean toward~Park'street, RPZ 40% pavement, deadwood #0 6~inches :diameter; `thin foliage CC, • aerate;" organic mulch: 2 56 CL 21.9, 185, •1"7, 342 Fill +•compaction in entire RPZ, Ganodermk oregonense fungus . conks~near base, bark~beetles at eye level, Daldinia conccntriaq fruiting on' 1\lorth Check- ownership of this tree. REMOVE: URGENT Management Area "A"' Black and Coast Live;0aks, many w.% multiple; stems " ~ ~ Fence; 'thin stand. by 25 - 3096, RCE: 2 57 M P -, 34.8 Imbalanced to West, exposed + damaged roots, girdling roots Aerate, remove girdling, roots, 'Crown Thinning on dVest side: 2 - " 58' MP .34.2 Imbalance8-toward Pleasant Street, grade°cut in RPZ Aerate; • Crown Thinning: 2 - 59 B 20.7 Girdling root, leanaargets tree #.=60~and table, cut grade" - 1tCE; aeration, .organic mulch;, "CC; Crown Thiiin'ing:_. '2 60- CL 15:8, 14.3 ~ Soil compacted, 'lean targets table, roots hit by tractor;(2x), - emtedded'bark ®2:.ft " Crown Reduction (limb, over table),, RCE, aeration;. organic mulch, CC, ;cable: 2 6i B 145 Deadwood o 4 inches diameter • RCE, aeration; ~ .organic; mulch: 2 - 62 CL 2A:3' Numerous °stubs _ - Aeration, .organic .mulch, CC: 2 .. , . ' :'• .. ~ 6 . 63 CL 15.3, 13b;'9:9, 8:3 ' PavementFin RP2, RPZ cut3'ft, deadwood to' S•inches, scant .foliage REMOYB: 2 . 64 CL :15.1 Lean;targets Palk Avenue,, RPZcut 2wft; 5 ft.from tree #f,3 which .. id diseased,.. deadwood. to 3 inches diameter Aeration, organic' mulch, CC: '3 65 CL 19S ., Leanaargetsawo tables ~ '. -" RCE; aeration, organic mulch; CC, Crown Thinning . _ over tabled:, 2 • 66 B 1ErS, 165' Lean targets table. and bench , crotch ®2 ft. w/ imbedded bark - . .. RCE, aeration 'organic mulch, CC, cable; 2 _ 67 CL 13:7 Hollow base,fo>2.ft;, thin foliage RCE, aeration,. organic =mulch, CC: 2 <68 CL 226• - Lean .ta.rgets open an2a; to West; roots heaving on uphill side of. - lean, Ganodnma oregonense fruiting,, base. REMOVE:' URGENT - 69 CL 26:7 ~ Lean,targets open area; • roots heaving soil on theuphill~"side of.the lean, cavity is cement,filled (and cracked), leanng.into.tree #70 REMOVE: URGENT 70 CL 24.3;. 22;6 Imbalanced, 4096' pavement. in RPZ, Oak Root• Fungus,has killed 70% of'bark.on Northern stem REMOVE of Brace + fence: URGENT 71 CL 20.2 Oak Root. Fungus,-killed'70% of root crown bark REMOVE:URGENT 72 CL 324 Exposed'roots w/ missing°bark; embedded bark ®12=ft RCE, CC: 2 ' - 73 CL 33 Lean .targets open. area to Southeast; • roots heaving soil , ' Oak Root Fungus on Root Crown, decay ®broken stem 18 inches across, ;deadwood to `4 inches diameter • RCE, CC, Crown Thinning: 1 74 B 26S Six inchdiameter cavity®5 ft, I~ecay,~ 6 ft, lean targets open area to `forth. , 'RCE, CC, .Crown Thinningd` 2 75 CL 395 RPZ is 3090°pavement,. imbalanced to mouth, exposed roots, " girdling roots; ;thin .foliage in pails of canopy RCE, remove, •girdling;,roota, remove pavement fmm RPZ: 2 17 76 B 19S - .Lean targets open area to South; avity'®`7 ft (lft x 6 in) :RCE,:°. CG: 2 • 77 Cl 26.1, 28;4 RPZ cut, bleeding .base, prominent specimen at corner-Bark missing 1_ft•sg Howard.Streetside ~'2 ft height, Bark missing (from tractor)-on;;Park,Avenue side, limbs crossing ®4 ft, thin; `foliage, twig blight RCE; :CC: 1 78 CL 421 Imbalance targets children's play area, Root Crown >50% killed by Oak Root Fungus _ REMOVE` or RCE, CC, ;move-children's play area and exclude' people: ,URGENT 79 M P 38.8 ~ Crotch with buried bark ®20 ft Cable: 1 80 IvI P 25.8 Girdling roots ' Remove girdling.,roots 81 M I' 38:8' Root Crown damaged (ty .tractor) ` ' No action ~ thie time 82 M P 13.6 Pavement in 30% of`RPZ, two tops ' Remove weaker of 2 'tope; CC: 2 ' •s " Ma nagem ent Area "B'--'' 35 Coast Live + Black Oaks up to,-12 inches diameter. Remove 20-303'0 of` oaks, 1tCE + CC those retained: 3 84 CL 26.3 ~ .. Wounds ®ba`se callused closed . RCE, CC: 3 85' CL 25.1 Leantargets low use;area; heavy low limbs ' RCE, CC: 3 , 85 CL 23!1 Lean targefs<low use:area . RGE, .GCs 3 ST CL 24:7 Wounds ®base callus covered • RCE, CCs 3 ' 88 CL ,.. • 19.6' ~ Gherry phums below . RCE: •3 . ~ I)ISCZJSSION 18 This. site has two parts which. are distinctly different, the upper irrigated turf area and the lower dry area Large coast `li a oaks, dominate the park: The entire park was_a graveyard from about 1855'to 1879,. `The nearby reservoir was originally constructed in 1:869 and coast: lire oaks were planted there sometime later so those trees by. the reservoir are less than 1.1.1 years old. In the upper irrigated area the,water regime favors the development of fungi and now disease =is amajor problem killing roots and weakening tree structure. Pythium root rot was isolated ffrorn oak roots. _IVo. ~Phy#.opthora root rots were isolated. Oak Root; Fungus Armillaria mellea has killed bark visible at this time, on trees # 70,~ 71,` ~73' and, 78. -Root crown excavations, are recommended for more insights on root crown disease :involvement and management. ~ Ganod'erma fungus is fruiting on the`base of trees.:# 5Ei and #b8. Canopy imbalance and lean both: aggravate the safety problems associated. -with :the afore mentioned root diseases. 'The lower in the: trunk the:wood is weakened by disease the more: likely it is the tree: will fall prematurely., . . Roots and coil were; analyzed by a specialty laboratory for nematodes.:, None were :found in the .sampled roots, though; some: were found in the soil. The nematode species found ;and therpoptilation levels suggesfs~`that future plantings 'at this site with young trees. may be a .problem, but thaf older, specimens and adult trees will likely not be so adversely effected. NEMATODES FOUND'Il~T SOIL: ®. Lesion , Pratylencllus sp. 50/liter ®Root' Knot, Meloidogyne sp. ~ 50 /a'#er • :Spiral. 5Q/:liter ® Ring, Crnconemella sp. 700/li'ter Gracilacus sp: 50/liter Many root crowns Have been repeatedTy.wounded by a tractor or mower which -will lead. tq decay. Most of~ the root crowns could~benefit from root, crown . ~ ~ excavation for ,disease management especially in the irrigated area. ~ Hydraulic excavation is the most effective method, which is best accomplished during, the winter' months.. Manual excavation :can be undertaken at any time.. Once °the crowns; are excavated they should be appraised for structure.. and health by DendroTech. Two pathogenic root decay fungi; Oak Root Rot and Ganoderma fungus are visible in `the irrigated site:; 'These ;fungi consume root 'and .trunk tissues, eventually leading to failuref of `roots, or base of trunk or to premature death. These fungi flourish. under hi' h soil ;moisture conditions such as at the upper g. area ~of Oak. Hill Park where the soil is nof,allowed to ~'Y during the warm season. • Soil oxygen is commonly a major ,limiting factor for roots. ~ Excessive irrigation g . fills. pore spaces. in the°~soih with water; displacing th'e essential air and` thus oxygen. Roots in-~an :ox en. . yg poor environment: perish 4uckly. With,.a reduced ~, root system, trees are less able to take in water and nutrients, and susceptibility to . root diseases ~is increased. ~ , Average annual. precipitation; for Petaluma ~is 24:1 inches per, year: The irrigation • of `upper Oak. Hill Park has averaged about X48 inches each year for the past three years.. The~sum of the natural, precipitation and. the irrigation water is about. 72 inches (6 ft) of water each year. 'This is about three times the average natural amount of moisture each year. C®NCL,LTSION-S/IZECOI!IElii1ENDA'TIONS 20 ~~ The frees. at this park, are, nearly all mature! and 'they ,suffer from a combination of problems..:' Many problems are assocated''with. the unnatural and problematic routine, warm .season ;irrigation. in the upper, area, In the lower area. the trees . suffer also;'but from a different group of parasitic: fungi. =the wood. rofters:: In both. areas; the trees .are impaired strueturally~ by the progressive loss of supportive wood, making, tlieiri 'hazardous. .. .. . Managing .hazard trees can be :difficult: Accurate.:hazard detection and appraisal is chahenging sandrequires routuie~~inspectons by a professional versed with a diverse: array of plant management skills. To,mnimize tree hazards_ at this site follow all recommendations outlined in the inventory. .Remove. as many hazard trees 'as possible` asaoon as is practi'cal`. Routinely monitor .this stand 'and. others for haardous conditions. Most of the tree canopies overlap and thus compete for light. The competition ~: for the soil `resources of moisture and nutrients are:, the same. As.'trees grow the .roots explore <new soil ~to; access needed resources.. Eventually they- reach a .point where. they. are competing with each other for the limited:-resources. Thinning the stand is one way to deal with this,.. ~ Another is to .provide supplemental nutrients and moisture,, because of~ the complications associated with irrigation this, is 'nof a realistic option. The removal Hof' structurally weak indi~i'duals is ,the prefered away to th'in` thi's `stand.: The openings resulting from tree: reino~als ae good places to start new young rees: - ~ , ,,. Start .introducing wider age structure, into, thi's ~ population by planting arees to replace those .lost or slated' for remo~aL° $ave all seedlings. and saplings in appropriate "locations by erecting protectipe fences around .select specimens or predetermined. areas: Providetree chip mulch for natural acorn seeding in selected ;areas. Consider_:planting acorns directly or .1'arger specimens:' All_ plantings will benefit; from- aggressive weed; control and irrigation for the :first two or three dry seasons.. An interpretive .trail describing the :oaks, their. environment .and the historic conditions of Oak Hill Park would'be an~ interesting ..means. of cultivating- interest . -. - and;encouraging. care-:by:park. users. A. planting; program, where trees are assigned .. ~~ ~ - to specific :people will also 'foster feelings of . concern for° and involbement: with ' ~ the trees. -' ` - Any-trees which are removed: or':fall 'should be sectioned, sanded and the rings counted.:This a of activity may be something .the Citizens Advisory tyP Committee may be. interested in coordinating or `administer. Management" Areas A and B are the only areas. with. younger trees. These two areas should be fenced. for protection after ahe recommended thinning'~process. Starting r September 1.990 fertilize the irrigated. upper area with nitrogen. Apply at'"the rate of four pounds actual nitrogen per 1,QQU,,square feet of .soil surface `with a broadcast fertilizer: Irrigate immediately for 20 minutes. - ~ Excavate all root :crowns outlined in: the. inventory,, all root crowns involved 21' . , .- -. with root disease(s) and a1T,root crowns ezY-ibiting ;raised, grade, (when Root Flare 'is not visible)'. This critieah action could be well .done by a group 'of volun#eers. -- Use ~ water is'the fastest,. safest and thu , Drou 'ht conditions; must be consideredleast costly method to excavate crowns. .. _ - s year. ~ Perhaps a water truck with . a ~ ' - hose could import water for this:-project or wait for improved conditions to- avod .public outcry over water use. ~ ' -~ The'landscape possibhties~:at ;this site are, unusually exciting. Several of the Advisory Committee members are skilled in various aspects of plant . management. and landscape desgr.: `These individuals 'are' well- versed on the - limitations associated. with. drought adapted native oaks. Perhaps the Committee can= develop some appropriate landscape enhancerrients without `imperiling the lage oaks. ~. ~ , p,' oaks ~aretto h elto t erne tur ts~hou~be eliminated from. the upper ,area if 'the ~ , - po gation should ~be terminated, ~in late Fall or 'early winter when cool season precipitation-starts.. Next spring irrigation should be discontinued. The, oaks. will~'suffer from 'the transition o€ ahe water re '~me ~. and~some die-back should be expected The alternative,,is the°continuance of irrigation 'and the continuance of irrigation. induced root loss and prematur:,e tree loss. - r~ ~. - ~ - ,. 1VATi:TRAL,;~IIS`I'ORY~OF OA~CS~ GIZO~NG AT OAK HILL PARKS 2 Black Oak, ~Quercus kelloggii; ;is the ~rnost widely distributed. oak in. California, found over 18% of the ~state..Ths deciduous tree,grows ,fo :almost 1QO feet in height in mixed evergreen.. forest; yellow pine forest and northern oak woodland. This species is shade tolerant;:: a weak compartmentalizes and. is an inhabitant ~of well drained,. dry and gravelly stes~below 8,oQ0 feet elevation. It ranges from San Di o coon , to Or on, .with the .densest areas being in the ~ ty eg Northern :Sierra and. Coast Range, Coast Live Oak 'Q: agrifolia, is an evergreen tree ao 75 feet tall and wider. It is .commonly found near the coast from Mendocino :county to the Mexican border. This species likes dry sites; yet may inhabit waterways in more arid. locations. Coast Live Oak is best"known in Southern California where it may .live to be 250 years of age. It grows blow 3,000 feet on rocky hills and in valleys of the Coast Ranges: Valley Oak Q. lobata is the.largest of the Western oaks growing; to over 100:feet tall. This species i~abts deep well, drained ~~alley_ -soils below 2;000 feet elevation.`in the:~Sacrarnento Valley'°and the Coast Ranges: and:''is considered. to be. highly resistant` to.~0ak, Root Fungus. This oak' species: is recognized. to .have lost a' large percentage of-.its original habitat area..and to suffer from poor regeneration in California. ,., _ SELECT REFERENCES 2`3 Bega Robert V. 1979. DISEASES OF PACIFIC COAST CONIFERS. Agriculture Handbook #521:. Bush, `Lisa. ,Rocky Thompson. ;1989: ACORN TO OAK. . Circuit Rider Productions, Inc: Windsor-, CA. Griffen,James R. William.. B. Critchfeld. 1976. ~ THE DISTRIBUTION OF FOREST TREES'`IIV CALIFORNIA. USDA;. Forest Serviee Research Paper PSW - 82/1972. ' Raabe, R. D:, A. H: McCain.1987.- • ARNIILIARIA ROOT -ROT. UC Cooperative Extension. . 1990.. FREMONTIA, Tle Year, of the.' Oak. July.. ` California Native Plant Society, 'Sacramento, CA..