![[Chestnut Trails entry sign]](../images/TR2001_Sign.jpg)
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Native protection zones form part of the Chestnut Trails community.
An initial inspection of the trees was made in 1997, the results of that site visit were provided in a report dated 8/4/1997. A second inspection was made in 1998 with the report dated 7/14/98. That report included a recommendation for an ongoing assessment of the trees.
A proposal was requested, the proposal was to provide consultation services on the following basis.
Individual tree inspection begins at ground level. Here tree species, soil quality, rooting conditions, soil level, irrigation and drainage characteristics can be observed. The level of soil compaction may be tested to evaluate the aeration capacity of the soil. The quality of the soil can be assessed in its ability to contain and disperse available moisture. Some soil types are easily compacted and although they are high in nutrient quantity, little of that nutrient quality is available to the growing tree. The heavy equipment used in construction or frequent traffic of any kind can cause sensitive soils to become compacted. Compact soils cause problems by restricting the trees ability to discharge the gasses produced as part of the growth cycle. The visible parts of the tree; the trunk, branches and leaves live in balance with the unseen roots. Inhibited root growth causes a tack of vitality and a lack of growth within the whole tree.
If signs of stress are present a soil test may be made at this time to assess the fertility of the soil. Testing establishes the presence and degree of vital nutrients. Vital soil is essential to vital tree growth the presence of nutrients and organisms within the soil mean that growth can continue. An imbalance of nutrients can cause poor vitality; often exhibited by leaf discoloration or lack of annual growth. Poor nutrition will slow growth and can diminish the trees natural defense mechanisms and expose the tree to disease.
In nature few tree species grow alone. The forest is their natural and protected setting. Because of this reality and irregardless of a trees origin, trees in a landscape setting demand special attention, each individual tree is the product of the local environment. Their success and well being rely on our care.
Looking at the overall picture, the health of the soil, turf and other plants and trees can reveal the cause of disease, or indicate potential problems. The presence of certain species of fungus can indicate decay. Certain decay fungi may destroy support tissues and leave conductive tissues unharmed. The tree may appear healthy and continue to grow until the internal decay outpaces the new outer growth.
A root crown examination may be necessary if root decay is suspected. By removing the soil at the base of the tree the location, health and condition of the absorbing and support roots can be determined.
In the primary examination of the root crown and trunk a mallet is used to test for loose bark. Bark lifting can indicate dead or hollow areas and give signs of the presence of decay in the root crown zone and at the base of the trunk. The mallet may be used to "sound" for decay but this has limited reliability in some species. If decay is suspected the tree will be tested using the Resistograph. The Resistograph is an instrument that inserts a constant velocity probe into the suspect area of the tree. The resistance to the probe is graphed by the machine. The graph profile can tell a great deal about the internal character of the wood. Internal defects can be detected, cracks, hollows and early stage decay. The type of decay and its effect on the stability of the wood depends on the species of fungus involved. Soil and root tissue samples may be taken to determine the cause of disease by laboratory testing.
The inspection continues with an evaluation of the tree crown, first by eye or with the use of binoculars then, if necessary, by climbing into the canopy of the tree. The color, size and condition of the leaves, trunk, branches and twigs is assessed. The form and formation of all the trees components give information about health, vitality and structural strength. The crown density, the number of leaves on each stem, and past and current growth extension, indicate current health and previous problems. Changes in growth rate in older growth may indicate prior disease or injury .An evaluation of the general growth habit will reveal any problems related to vigor, or the genetic component of tree growth. Previous treatments such as pruning or cabling are observed, the quality of the work, and its effect on the tree. Any growth abnormalities are noted: weak limbs, discolored or missing bark, cracks or cavities in branches or trunks and the presence of disease within the canopy of the tree in the form of leaf blight, stem canker or insect activity.
Trees produce adaptive growth to compensate for the stress related to growth and injury .The shape and formation of limbs and trunks can show the ability of the tree to compensate for weakness or indicate internal problems that may lead to failure. The interpretation of these changes in form is part of a growing body of knowledge pioneered in Europe. The knowledge is not new but the application is: Dr. Claus Mattheck of the Karlsruhe Institute and colleagues, have developed a system of structural evaluation based on the bio-engineering principals. I have chosen to use this approach to augment my own knowledge and experience. The observations and results of the field work and testing where applicable are given in the body of the report. They are followed by a statement of my conclusions and my recommendations for treatment.
In the initial report the wooded areas within the community were delineated into zones. The zoned were identified based on the proximity of residences, roads and pathways. In addition areas of high target rating were identified within the zones. The target rating is based in part on the rate of occupancy of a path, road or home. The location of the zones and high target areas is shown on the enclosed sketch map.
Zone 1. Trees on the north edge of the stand between 201st and 200th pl. With an area of high hazard potential identified in the trees on the northern periphery of the stand, Immediately adjacent to the houses on 200th Pl. Two areas of endemic root disease have been identified within this area.
Zone 2. To the windward side of 201st St. Less exposed than zone 3 but this zone contains a known area of root disease, previous failure has occurred within this zone.
Zone 3. Adjacent to the end of 201st St. on the hillside exposed to the full force of the prevailing wind. All pre-existing protection to the south of zone 2 was removed during development.
Zone 4. Along the ends of 32nd Dr. and 33rd Dr. This area also has a known disease site and is somewhat exposed to prevailing winds.
The remaining areas have a lower likelihood of tree failure in normal conditions. There are separate issues within these areas, issues related to the decline and death of trees through natural causes and the identification of trees with defects or other disease. The problems related to endemic root disease are of more concern than individual hazard trees. Root disease continues to lead to the failure of whole standing trees.
![[Zone 1 tree fell in a storm]](../images/TRstorm.jpg)
The
tree shown at left failed during a wind storm on December
15th 2000. The tree was located in Zone 1. The wind during that
December storm was relatively unusual in that it came from the North.
The photograph at left is taken from the north looking south.
Trees produce adaptive growth to compensate for the stresses induced by growth weight and wind exposure. Generally, trees are well adapted to the pressures of storm force winds. The exceptions are; when the tree is newly exposed, has poor aerodynamic form, is subject to root disease and is exposed to strong winds from a different direction than the norm.
![[Woodland situations]](../images/TRdisease.jpg)
In
woodland situations the action of decay fungi form an essential part of
the cycle of events. Their presence is necessary to the health of the
forest community. Decaying wood provides nesting materials, decayed
wood forms one of the organic components of soil. However tree decay
fungi can cause even healthy trees to fall over. Certain decay fungi
can become endemic on a site. Laminated Root Rot, Phellinus Weirii
is such a decay fungus. This pathogen is common in the Pacific
Northwest in stands of Douglas Fir and extends through a stand of trees
via root contact. The decay fungus attacks the support roots of the
tree while causing little damage to absorbing roots, it shows little
above ground symptom of disease other than a slight rounding of the
crown. The problems of root decay are exacerbated by exposure and wind
direction shifts, this is evidenced by the failure of the Fir in Zone
1. The Disease centers are shown on the enclosed
sketch map. As the map illustrates area D1 appears to be expanding and a new area D5 was discovered toward the eastern end of zone Z1.
As stated in previous reports, the native protection
zones obviously provide a great resource for the community, but they
cannot be regarded as static. These areas are continually growing and
changing. The exposure caused by the development of Chestnut Trails and
the presence of disease makes the change more dynamic and demands a
more active response. If the protection zones are to continue to be an
asset to the community stratagem for their maintenance must be
continued. ![[Zone 1 disease center]](../images/TRconclusion.jpg)
Chestnut
Trails community has begun by establishing a tree inspection program
and arranging the removal of hazardous trees. The replacement
program is underway and a number of disease resistant trees have
already been established.
It seems clear that the disease centers in Zone 1 are expanding. Zone 1 is different from the other zones in that it is exposed to both the prevailing wind from the south, south east or south west, and wind from the north. The other zones are somewhat protected from the north wind being on lee side slopes. As evidenced by the failures within the area action must be taken to limit the possibility of further failure. Their have also been some deaths among standing trees, the deaths are in suppressed Red Alder with the exception of a large Fir in Zone 3.
The trees within Zone 1 are of primary concern. Continued failure of trees that surround the disease centers is to be expected. I recommend that an accelerated program of tree removal and replacement is undertaken within this area. I have identified the trees that pose the greatest threat to the surrounding homes and prioritized their removal.
![[tree marked with yellow stripe]](../images/TRyellow.jpg)
The trees are marked in the field with paint encircling their trunk at
the lowest clearly visible point on the trunk. Three levels of action
have been prioritized. Trees marked with the yellow stripe are trees
that show relatively good health and form and that are not exposed
above the canopy of the stand. These trees should be monitored for
potential removal within 5 years. They are shown on the
sketch map with a Y.
![[tree marked with yellow stripe and two red slashes]](../images/TRyellowred.jpg)
Trees
marked with a yellow stripe encircling the trunk and two red slashes on
the north side, are trees that are closer to the center of known
disease sites and are prone to failure either by their location on the
edge of the stand or by their exposure above the general canopy height.
These trees are prone to disease and unusual wind stresses and should
be designated for removal within two years. They are shown on the
sketch map with a YR.
![[tree marked with red stripe]](../images/TRred.jpg)
The
final designation is for trees that are immediately adjacent to known
disease sites and are exposed to the full force of storm conditions
because of a lack of support from surrounding trees. These trees are
either standing alone within the group or on the edge of the group,
they also show poor overall form, with the majority of the sail area of
the tree high on the trunk. These trees should be removed within a
year. They have a red stripe encircling the trunk and are shown on the
sketch map with an R.
The removal of these trees will establish an opening within the stand. Previous plantings have taken the form of under-planting. The placement of trees under the canopy of the stand. This scale of removal will allow the planting of a larger number of trees within the opening. Previous recommendations called for planting trees on 15' centers within natural opening in the stand. Closer planting will be possible within the opening and trees may be planted as close as 6' apart to establish early canopy cover and reduce the growth of undesirable understory.
The list of recommended plantings follows:
Resistant Trees:
Immune Trees:
All deciduous broadleaf trees are immune, options include:
As in previous reports I recommend a mixture of deciduous and evergreen trees with an emphasis on the native and naturalized species. Alder is preferred where wetter conditions exist.
I hope this information proves useful, please let me know if I can be of further help.
Yours sincerely
Robert W. Williams C.A.
Consulting Arborist