wandoo crown condition 2008 - department of biodiversity ... · from each site for 2008 are shown...

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


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


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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.

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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


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




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


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


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 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 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


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



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


All trees have minor flagging


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


Minor to extensive on most trees

Minor to extensive on most trees


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




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)

wandoo crown condition 2008 - department of biodiversity ... · from each site for 2008 are shown...

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