wandoo crown condition 2008 - department of biodiversity ... · from each site for 2008 are shown...
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Wandoo Crown Condition 2008
Report of wandoo crown decline surveys, 2008
Kim Whitford, Liz Manning and Allan Wills
September 2008
Wandoo Crown Condition 2008
Report of wandoo crown
decline surveys, 2008
Kim Whitford1, Liz Manning2 and Allan Wills1
1Science Division, Department of Environment
and Conservation 2Wandoo Recovery Group
This report summarizes results from surveys of
wandoo crown decline completed in 2008 by
community groups, TAFE students, DEC staff
and volunteers using the method developed by
the Wandoo Recovery Group (WRG, 2005). The
WRG greatly appreciates the contributions of
volunteers who gave their time to complete these
surveys. Without their assistance this survey
work would not be possible.
The WRG coordinates this project to assess the
extent and severity of wandoo crown decline
across wandoo’s (Eucalyptus wandoo, Blakely)
natural range. Each survey is based on
assessments of individual trees along transects
that are typically 100 m long and 20 m wide and
located within forest, woodlands or remnant
wandoo stands (Figure 1). Each tree along the
transect is assigned to one of three diameter
classes and assessed to separately determine
the stage of decline (Figure 2) and the amount of
flagging occurring in the tree crown. Flagging is
the drying out and browning of leaf clumps in the
tree crown. The survey data is then summarized
for each site and these summaries compared
with those from previous years.
Copies of the Assessment Guide, survey sheets
and line drawings of crown decline stage are
available from the WRG Executive Officer, Liz
Manning on 0427 441 482, by email
([email protected]) or can be downloaded
from the ’Nature and Biodiversity’, ‘Managing WA
forests’, ‘Conserving our wandoo’, ‘Mapping’
section on the DEC website www.naturebase.net.
The links are:
www.naturebase.net/component/option,com_docm
an/task,doc_download/gid,634/ and
www.naturebase.net/component/option,com_docm
an/task,doc_download/gid,790/Itemid,984/
Training and location of community
surveys in 2008
WRG members and DEC officers conducted
twelve training workshops during 2008. About 70
people attended the workshops, learnt how to
survey wandoo stands for crown decline, and
contributed survey data.
Twenty-two monitoring sites have now been
established on various land tenures including
private property, reserves and national parks
between Chittering and Cranbrook. The survey
sites are widely spaced across the geographic
range of wandoo (Figure 1). During 2008 sixty-
nine transects were surveyed across twenty-one
of the twenty-two monitoring sites. A total of
2,690 trees along 7.1 km of transect covering
14.2 ha were assessed. Survey intensity ranged
from one transect per site to seven transects per
site.
Establishment of additional survey sites for long
term monitoring is encouraged as they improve
understanding of the extent and progression of
decline. Similarly increasing the number of
transects on a site greatly increases the reliability
of the surveys in reflecting the condition of the
trees across the site, particularly on those sites
where only one or two transects were surveyed.
The value of the transects is also greatly
increased when they are repeated in subsequent
years in exactly the same location; this is
particularly the case when only one, or a few
transects are completed on a site.
Crown condition in 2008 and changes
since 2006
The reports of previous surveys completed in 2006
and 2007 are available at
www.naturebase.net/component/option,com_docm
3
an/task,cat_view/gid,502/dir,DESC/order,name/Ite
mid,986/limit,5/limitstart,5/
Of the twenty-two monitoring sites now
established, thirteen have been monitored since
2006, four sites have been monitored since 2007
and four new sites were added this year. We
can’t comment on any change in crown
conditions at these four new sites, but these
initial surveys still provide a useful baseline
record for interpreting future surveys.
Summaries and interpretation of survey results
from each site for 2008 are shown in Table 1.
Table 1 also lists the number of transects at each
site. Figure 3 has summary graphs of the crown
distributions of crown decline stage and flagging at
each site. The colour assigned to each site in
Table 1 and Figure 3 is based on the relative
extent and intensity of flagging on each site, which
we interpret as indicating the likely prognosis for
the site. Green indicates sites with little or no
flagging, which we expect to improve. Red
indicates sites with extensive flagging; we expect
these sites to further deteriorate. The intermediate
colours indicate intermediate conditions. This
simple interpretation only considers the extent and
intensity of the current decline and does not
consider the vigour of the sites, i.e. the varied
capacity of individual sites to recover from a
decline event. However, our previous
interpretations of flagging in 2006 and 2007 have
been correct for most sites.
Interpretation of the progression of decline is best
on those sites with several transects and the
progression of decline is most clearly identified
when exactly the same transect is resurveyed
annually.
Sites that have improved since 2006
Eight sites show a small improvement in crown
condition; these are: South Bokal, Yilliminning
Reserve, Milli Roo Property, Wundabiniring Brook,
Maylinga, Crossman Reserve, Foxes Lair
Reserve, and Kupara Reserve.
Flagging is at low to very low levels at South
Bokal, Milli Roo, Wundabiniring Brook, Maylinga,
and Crossman Reserve. Consequently, we expect
these sites will continue to improve.
Flagging continues at Yillimining, with almost half
the trees showing some flagging in 2008.
One third of the trees have minor flagging at Foxes
Lair Reserve and half the trees at Kupara Reserve
show minor to moderate flagging. This flagging is
not particularly extensive or intense and the crown
decline on these sites is expected to stabilize and
the trees crowns continue to improve.
Sites that have worsened since 2006
The condition of the tree crowns has deteriorated
slightly since 2006 on three sites (Strathairlie
Pastoral Lease, West Dale and Paruna Sanctuary)
and clearly deteriorated at another site, Karakamia
Sanctuary. The changes in crown condition
observed at Paruna and Karakamia Sanctuary’s
are consistent with observations of flagging
reported in previous years. Based on the flagging
observed in 2008 we expect the trees on these
sites will continue to decline.
In contrast the observations of changes in crown
condition at Strathairlie Pastoral Lease and West
Dale are not consistent with flagging observed in
previous years. Flagging on these sites was minor
in 2006 and 2007 and remains so in 2008. We did
not expect these sites to deteriorate and the
current flagging does not indicate continued
decline.
The trees at Mission Road and Batalling also
appear to have deteriorated, however these sites
require a field inspection as the response appears
to be inconsistent with the previous surveys.
Figure 1. The location of wandoo crown decline survey sites. Colours of the markers indicate the relative
outlook for the trees at each site (green = good, red = poor) based on the amount of flagging observed.
5
Figure. 2. Line drawings used to assess the progression of crown decline. The condition of the crown of
each tree along the survey transects was scored according to its stage of decline.
Sites unchanged or not previously surveyed
The condition of the tree crowns at two sites,
Bennelaking and Goldmine hill, is unchanged
since 2007. Goldmine hill has no flagging, but the
intensity of the flagging has reduced substantially
at Bennelaking since 2007.
The location of transects has changed at Gorrie
Road; however, the site shows only trivial flagging
and has probably changed little since 2006.
There were four new sites surveyed this year: 12
Mile Reserve, Stenes, Warrinup Reserve, and
Morgan. The tree crowns at 12 Mile Reserve
showed advanced decline, but with only minor
lagging on some trees, this site would be expected
to improve. The Stenes site had tree crowns in
early to intermediate decline with minor flagging on
half the trees. The site is probably stable and
should recover. The tree crowns on Warrinup
Reserve are in similar condition and should
recover. The Morgan site shows a greater amount
of flagging than Stenes and Warrinup and further
decline on this site is likely.
Conclusions
The addition of four new survey sites, the resurvey
of sites not surveyed in 2007 and increases in the
number of transects at six existing sites are
encouraging expansions of the survey project.
There are no obvious geographical trends in crown
decline across these sites in the southwest, with
sites in good and bad condition widely distributed.
Wandoo crowns can decline quite dramatically
over a period of one or two years. This is clear
from the condition of crowns at these and other
sites that have experienced decline events.
However, in the three years these survey sites
have been monitored we have not observed any
dramatic change in the condition of the tree
crowns at any of the survey sites. The three years
of our observation has been a period of relatively
gradual crown decline or improvement on these
sites.
The variations in intensity of flagging that we have
observed and the varied vigor of the response to
the loss of leaves is of interest in understanding
the progression of Wandoo crown decline and the
many factors that may influence the strength of
decline and recovery. These surveys demonstrate
that although the amount of flagging observed
does usually indicate the future condition of trees
on the site, this is not always the case. Sites that
respond vigorously to extensive flagging (e.g.
Kupara and Yillimining) can quickly regrow lost
crown and consequently may not deteriorate
rapidly after extensive flagging has occurred. In
contrast, sites such as Strathairlie and West Dale
that do not respond vigorously to a minor flagging
event can deteriorate progressively as this minor
flagging continues over subsequent years.
The continued monitoring of all sites will provide a
better understanding of the progression of crown
decline on individual sites and across the
southwest.
Table 1. Summary and interpretation of wandoo crown decline survey results from 21 sites. Surveys based on the method described in WRG (2005). Colours indicate the relative outlook for the trees at each site (green = good, red = poor).
Site Name Flagging summary 2006
Flagging summary 2007
Flagging summary 2008
Crown Decline Stage 2008
Changes at site since 2006 and current outlook Number of transects 2006
Number of transects 2007
Number of transects 2008
Trees per ha 2008
Goldmine Hill Not surveyed
No flagging No flagging No decline evident
Not surveyed in 2006. Tree health has not changed on this site since 2007. No decline evident and trees are in good health.
not surveyed
1 6 218
Milli Roo Property
Trivial flagging
Not surveyed Trivial flagging Early decline Not surveyed in 2007. Condition of the crowns has improved slightly since 2006. Early decline with very little flagging. Probably crown decline will not progress.
5 not surveyed
4 268
Gorrie Road Trivial flagging
Trivial flagging Trivial flagging Early decline The location of transects changed in 2007; however, the site shows only trivial flagging and has probably changed little since 2006. Early decline with very little flagging. Probably crown decline will not progress.
4 6 7 177
Wundabiniring Brook
Not surveyed
Trivial flagging Trivial flagging Advanced decline
Not surveyed in 2006. The condition of the tree crowns has improved since 2007 and the amount of flagging has declined to very low levels. The crowns are improving and the site appears to be recovering. Probably crown decline will not progress.
not surveyed
6 7 224
Maylinga Trivial flagging
Trivial, with isolated extensive flagging
Trivial, with isolated extensive flagging
Early decline Crowns scorched in 2007. Some tree crowns have improved since 2006 but other crowns continue to decline. Early decline with very little flagging was observed in 2008. The tree crowns should recover. Probably crown decline will not progress.
1 1 2 310
South Bokal Minor flagging on some trees
Minor flagging on some trees
Minor flagging on some trees
Early decline The condition of the tree crowns has improved slightly since 2006. Early decline but flagging increased slightly in 2007, compared to 2008. Possibly crown decline will not progress.
1 1 1 128
Mission Road Minor flagging on some trees
No flagging Minor flagging on some trees
Early decline The tree crowns have deteriorated slightly since 2006. There was some improvement in crown condition and less flagging (i.e. no flaggng) in 2007, but flagging reoccurred in 2008. Early decline. Possibly crown decline will not progress.
1 1 2 185
Strathairlie Pastoral Lease
Minor flagging on some trees
Minor flagging on some trees
Minor flagging on some trees
Early decline The trees on this site have deteriorated slightly since 2006 but have changed little since 2007; however flagging has increased slightly since 2007. Possibly crown decline will not progress.
2 2 2 156
Crossman Reserve
Minor flagging on some trees
Not surveyed Minor flagging on some trees
Intermediate to advanced decline
Not surveyed in 2007. The tree crowns appear to have improved slightly since 2006 and there has been a slight reduction in the number of trees flagging. Though decline is advanced, flagging is minor and possibly crown decline will not progress.
7 not surveyed
5 161
12 Mile Reserve
not surveyed Not surveyed Minor flagging on some trees
Advanced decline
Not surveyed in 2006 or 2007. The trees are in advanced decline but few trees are flagging, indicating the tree crowns may improve. Possibly crown decline will not progress.
not surveyed
not surveyed
2 170
West Dale Minor flagging on some trees
Minor to extensive flagging on some trees
Minor flagging on some trees
Advanced decline
The condition of the crowns has declined slightly since 2006. The site has advanced crown decline. Flagging was minor in 2006, but extensive on some trees in 2007, and minor flagging occured in 2008. Possibly crown decline will not progress.
4 4 4 105
Foxes Lair Reserve
Minor flagging on most trees
Minor flagging on some trees
Minor flagging on one third of the trees
Advanced decline
The condition of the crowns has probably improved since 2006; however the apparent changes may be due to changes in the number of transects. The site has advanced decline. Flagging decreased from 2006 to 2007 and remained at similarly low levels in 2008. Possibly the crown decline will stabilise and the crowns will recover
1 4 3 252
Yilliminning Reserve
Extensive flagging on some trees
Minor flagging on some trees
Minor flagging on half the trees
Early to advanced decline.
The condition of the crowns has improved substantially since 2006; however the apparent changes may be due to an increase in the number of transects. Flagging increased from 2007 to 2008 and is at low levels on half the trees. This increase in flagging may progress the crown decline. Possibly the crown decline will stabilise and the crowns will continue to recover.
2 2 4 124
Stenes Not surveyed
Not surveyed Minor or moderate on half the trees.
Early to intermediate
Not surveyed in 2006 or 2007. Early to intermediate decline, most trees have lost some terminal foliage. Possibly the crown decline is stabilising and crowns will recover, but the decline agents are still active.
not surveyed
not surveyed
3 257
Warrinup Reserve
Not surveyed
Not surveyed Minor or moderate on half the trees.
Early to advanced decline.
Not surveyed in 2006 or 2007. Early to advanced decline, most trees have lost some terminal foliage. Possibly the crown decline is stabilising and crowns will recover, but the decline agents are still active.
not surveyed
not surveyed
4 144
Kupara Reserve
Extensive flagging on some trees
Not surveyed Minor or moderate on half the trees.
Early to advanced decline
Not surveyed in 2007. There has been some slight improvement in crown condition since 2006 and the amount and extent of flagging has decreased. Possibly the crown decline is stabilising and the crowns will recover.
1 not surveyed
1 130
Morgan Not surveyed
Not surveyed Minor flagging on most trees
Intermediate decline
Not surveyed in 2006 or 2007. Intermediate decline. Majority of trees with the majority of their terminal foliage intact. Decline agents currently or recently active. Progression of the decline is likely.
not surveyed
not surveyed
3 150
Bennelaking VCL
Not surveyed
Extensive flagging on some trees
All trees have minor flagging
Intermediate decline
Not surveyed in 2006. Intermediate decline. Crown condition has not changed since 2007. The intensity of flagging has reduced since 2007 but all trees now have minor flagging. Progression of the decline is likely.
not surveyed
3 3 212
Batalling Not surveyed
Trivial flagging Minor or moderate on most trees
Early to advanced decline
Not surveyed in 2006. The condition of the tree crowns has declined substantially since 2007 and the amount of flagging has increased. Progression of the decline is likely. This site has deteriorated substantially since last year and requires a field inspection.
not surveyed
4 4 211
Karakamia Sanctuary
Extensive flagging on some trees
Minor to extensive on most trees
Minor to extensive on most trees
Intermediate decline
The condition of the tree crowns on this site has declined slightly since 2006 and the number of trees flagging has increased. Progression to advanced crown decline is likely.
1 1 1 300
Paruna Sanctuary
Extensive flagging on most trees
Extensive flagging on most trees
Extensive flagging on most trees
Intermediate decline
The tre crowns on this site have declined since 2006 and extensive flagging has continued. Majority of trees with the majority of terminal foliage lost. Progression to advanced crown decline is likely.
1 1 1 142
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Figure 3. (Left hand side) The percentage of trees at each site assigned to the six crown decline stages. (Right hand side) The proportion of flagging leaves in
the tree crown at the time of assessment. Classes are 0%; < 20%; 20%–50%; and 50%–100%. Colours indicate the relative outlook for the trees at each site
based on the current extent and intensity of flagging (green = good, red = poor)