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<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2>Hi Vojka,</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2>Here is how I might approach this
challenge:</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2>1. Establish what the actual vertical soil and root profile
is beneath the lane (or immediately adjacent to it on the tree side).
</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2>2. If there is a significant density of woody transport
roots (>20mm in diameter) within the proposed excavation depth, I would begin
by doing everything possible to persuade the engineers to reconsider their road
profile and sub-grades. Can the road be crowned up gently in the
area immediately opposite the trees? Would the engineers consider a
reduced base course in order to avoid having to excavate so deeply within the
critical root area of the tree?</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2>3. Once you have modified the road design as much as
possible in favour of the trees, re-assess the residual anticipated impacts to
the tree roots. </FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2>4. If the anticipated root impacts remain
unacceptable, a modified excavation workplan is required to minimize root
impacts. I would begin by supervising some initial grading back of the
existing road base with an excavator with a clearing bucket and a competent
operator. Once you encounter the root horizon in earnest,
stop.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2>5. Whatever depth still remains to be excavated to
achieve an adequate bearing/frost-free depth should now be excavated through the
root horizon either hydraulically or pneumatically. My weapons of
choice are a septic truck with a high-pressure pump and hose with a
variable-pitch nozzle and a pair of hand-pruners. Work together with the
hose operators to remove smaller roots to facilatate better access to soils
further down. Play with the volume and pressure of the water to
minimize tissue damage to the roots as much as possible.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2>6. Once your road bed depth has been achieved, back
fill with a structural material(s). Work with the engineers to come up
with a base material profile that will work for both the roots and the
road.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2>This is messy, slow work, but can often mean the difference
between a viable tree after road construction and a dead
one.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=606293817-04022009><FONT face=Arial
color=#0000ff size=2>Good luck,</FONT></SPAN></DIV>
<DIV> </DIV>
<DIV align=left><FONT face=Arial size=2><SPAN class=606293817-04022009>Jeremy
Gye</SPAN></FONT></DIV>
<DIV align=left><FONT face="Arial Narrow" size=2></FONT> </DIV>
<DIV align=left><FONT face="Arial Narrow" size=2>Gye and Associates - Urban
Forestry Consultants Ltd</FONT></DIV>
<DIV align=left><FONT face="Arial Narrow" size=2>Victoria, BC</FONT></DIV>
<DIV align=left><FONT face="Arial Narrow" size=2>Tel: (250)
544-1700</FONT></DIV>
<DIV align=left><FONT face="Arial Narrow" size=2>Cell: (250)
883-4533</FONT></DIV>
<DIV align=left><FONT face="Arial Narrow" size=2>Fax: (250)
544-2059</FONT></DIV>
<DIV> </DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> canufnet-bounces@list.web.net
[mailto:canufnet-bounces@list.web.net] <B>On Behalf Of
</B>2vojka@rogers.com<BR><B>Sent:</B> February-04-09 8:34 AM<BR><B>To:</B>
Canadian Urban Forest Network<BR><B>Subject:</B> [CANUFNET] pavement
construction near large trees<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV
style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">
<DIV>Hello Canufnet,</DIV>
<DIV> </DIV>
<DIV>I am reviewing a proposal to repave a lane in a well vegetated
residential area. Curently, the lane is paved with gravel and it
is proposed to replace the gravel with asfalt paving. The lane
elevation may no change, therefore, the asfalt paving when finished must be at
axisting grade, requiring at least 35cm deep excavation. There are a number of
large trees (the largest are two silver maples with diameter greater than 100cm)
in the close proximity of the lane. The excavation for the asfalt bed
will result in severing a great portion of the root system of those trees.</DIV>
<DIV> </DIV>
<DIV>The engineers are prepared to hand excavate around the trees and ensure
that no roots are severed....but they would like to have the root protection
requirements written in a form of construction specifications.</DIV>
<DIV> </DIV>
<DIV>I was wondering if anyone has dealt with a similar situation and
may have available construction specs addressing the above described
problem.</DIV>
<DIV> </DIV>
<DIV>Thanks in advance.</DIV>
<DIV> </DIV>
<DIV>Best regrds, </DIV>
<DIV>Vojka Miladinovic</DIV>
<DIV>Urban Forestry Planner</DIV>
<DIV>City of Toronto</DIV>
<DIV> </DIV>
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