Seasonal cambial activity and tree-ring formation of Pinus merkusii and Pinus kesiya in Northern Thailand in dependence on climate

Seasonal cambial activity and tree-ring formation of Pinus merkusii

and Pinus kesiya in Northern Thailand in dependence on climate

Nathsuda Pumijumnong *, Toonsak Wanyaphet

Faculty of Environment and Resource Studies, Mahidol University, Nakhon Pathom 73170, Thailand

Received 28 January 2005; received in revised form 3 January 2006; accepted 30 January 2006

Abstract

This study is aimed at characterizing the cambial dynamics and its dependence on climate of two pine species native to Thailand, Pinus merkusii

and Pinus kesiya and at describing their climatic response over 148 years. The samples for cambial activity analysis were taken monthly from

March 2000 to February 2001, and the cambial activity was determined by counting the number of undifferentiated cell layers between mature

xylem and phloem in transverse sections. Statistical analysis was done using Pearson’s correlation. For the dendroclimatological analysis, samples

were collected from the same sites in March 2004, and dendroclimatological standard techniques were applied.

The results indicated that soil moisture influenced the cambial activity of P. merkusii and P. kesiya, however that rainfall and temperature had no

significant effect on the cambial activity of both species.

The response function described the relationship between tree-ring widths indices and monthly rainfall and temperature and revealed that the

growth of P. merkusii at Hung Boung depended positively from rainfall in May. P. merkusii at Bao Kaew, however, had a positive correlation with

rainfall from previous November to current July, whereas temperature in the preceding autumn and winter should be above-average and in the

current spring and summer should be below-average. P. kesiya at Nong Kra Ting showed a slightly positive correlation with rainfall from February

to June, but a strong dependence on rainfall in September.

It can be concluded that the study of cambial activity could support our understanding of intra-annual variations and duration of tree-ring

development, whereas the response function could help explain the average response of tree-growth to climate.

# 2006 Elsevier B.V. All rights reserved.

Keywords: Dendrochronology; Tropical pines; Thailand; Cambial activity; Tree-ring formation

www.elsevier.com/locate/foreco

Forest Ecology and Management 226 (2006) 279–289

1. Introduction

Few subtropical tree species in Southeast Asia have been

successfully used for dendrochronological research, in

particular teak (Tectona grandis) and pine (Pinus spp.).

Various approaches have been tried, e.g. dendrochronological

networking and dendroclimatology with teak by Pumijumnong

et al. (1995a). Moreover, Buckley et al. (1995) established a

pine chronology in Northeast Thailand. Later, D’Arrigo et al.

(1997) presented progress in dendroclimatic studies of

mountain pine in Northern Thailand. All these studies

provided information on the inter-annual but not on the

intra-annual variation of growth and on the duration of wood

formation. Likewise, whereas research has been undertaken

* Corresponding author. Tel.: +66 2 4415000x228;

fax: +66 2 4419509/4419510.

E-mail address: [email protected] (N. Pumijumnong).

0378-1127/$ – see front matter # 2006 Elsevier B.V. All rights reserved.

doi:10.1016/j.foreco.2006.01.040

to understand the reaction of teak and pine to the monsoon,

the basic mechanisms of tree physiology and cell development

recorded in the sequence of ring widths are not well understood

and need further investigation.

In Thailand, few studies have been published on the

seasonal formation of xylem, e.g. by Pumijumnong et al.

(1995b) for teak. But there is still a lack of information on

cambial activity, on its increase at the beginning of the growth

season and its decrease towards the dormant season, along

with temporal variations of these processes. None of these

studies compared the average climatic response of tree-ring

width series with the seasonal cambial activity, especially in

subtropical pine species.

The present study was done for two pine species native in

northern Thailand, Pinus merkusii (two needle pine) and Pinus

kesiya (three needle pine), which are considered the most

important ones with respect to reforestation of watershed areas

and forest conservation as well as to their potential for

dendroclimatology. It is focused on their intra-annual variation

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http://dx.doi.org/10.1016/j.foreco.2006.01.040

N. Pumijumnong, T. Wanyaphet / Forest Ecology and Management 226 (2006) 279–289280

in monthly growth during one growing season as well as on

their long-term average climate/growth response. We had two

main objectives, first, to compare the variation of cambial

activity between the two pine species with trees of the same

age, and among trees of the same species with different ages,

and second, to describe the climatic response of the pine by

means of dendrochronology.

2. Materials and methods

2.1. Study area

In order to obtain meaningful climate-related results, the

sites should be as devoid of human activities as possible. Two

study sites were selected for cambial analysis. The Bao Kaew

(BK) Silviculture Research Station is located at Bao Loung,

Hod District, Chiang Mai Province, at latitude 18.16N,

longitude 98.38E and 1036 m above sea level. Here, P.

merkusii is growing.

The Nong Kra Ting (NT) Pine Production Area is located

in the Om-Koi District, Chiang Mai Province, at latitude

17.98N, longitude 98.38E and 1070 m above sea level. Both

sites are about 36 km apart from each other. Here, P. kesiya

is growing.

The original forest at both sites is a mixed dry dipterocarp

forest where pine is the dominant species, commonly in

association with native hardwoods, such as Shorea obtusa,

Dipterocarpus tuberculatus, D. obtusifolius, Phallanthus

emblica, etc. The undergrowth consists of Imperata cylindrical

and Cycas siamensis.

The site for dendrochronological analysis was Hung Boung

(HB), which is located at Bao Loung, Hod District, Chiang Mai

Province, at latitude 18.16N, longitude 98.42E and 1025 m

above sea level. Here, P. merkusii is growing. Hung Boung is

very near the Bao Kaew site, about 4 km down the road, and

about 40 km from the Nong Kra Ting site (Fig. 1).

The soil at HB and BK is red-yellow podzolic and gray

podzolic of medium depth with a pH between 4.5 and 5.5 and a

good drainage. As for the NT site, the main soil is a reddish-

brown laterite with a depth between 100 and 150 cm; its texture

is sandy loam or loam over clay and loam to clay with a pH

between 6.0 and 7.0.

In northern Thailand the southwest monsoon brings

rain with a monthly average of 167 mm from April/May to

October; from November to March it is dry with only 23 mm of

rainfall per month. The average annual rainfall at the three

study sites is 1000–1400 mm. The annual average minimum

and maximum temperatures are 4 and 40 8C, respectively

(Fig. 2).

3. Methods

3.1. Cambial activity

The age of each tree was determined by tree-ring counting,

and the trees were divided into three age classes: 30–60

(young), 60–90 (middle age) and >90 (old) years old.

3.2. Field sample collection

Samples were taken monthly from the same trees (three

middle aged and old aged, each, in BK and four young aged and

middle aged, each, in NT) from March 2000 to February 2001.

The specimens include bark, cambial zone and some part of

wood tissue of the main trunk at breast height (1.3 m). Two

specimens were taken from the north- and south-facing sides of

each tree. The sample size was about 2 cm � 2 cm with a depth

of 2 cm using a chisel. They were fixed with 3% glutaraldehyde

directly at the study site.

In the lab the specimens were thoroughly washed with water

to remove any remaining chemicals and then infiltrated and

embedded with PEG 4000. Cross sections of 20–30 mm

thickness were cut using a sliding microtome. Safranine and

fast green were used for staining.

The cambial activity of the pine trees was determined

by counting the number of undifferentiated cambial layers

having narrow rectangular cells between the mature xylem

and phloem under the light microscope. Earlywood and

latewood formation was observed by anatomical character-

istics.

The soil moisture content was one of the parameters used in

this study. Soil samples were taken from each site at a depth of

30 cm. Their moisture content was determined by weighing the

wet soil samples, then drying them at 100–110 8C and

reweighing. The soil moisture content was measured season-

ally. The results were expressed as percentage of moisture

based on the dry weight of the soil.

3.3. Sample collection for tree-ring analysis

In March 2004, altogether 37 pine trees from Hung Boung

(7 trees, 28 cores), Bao Kaew (10 trees, 30 cores) and Nong

Kra Ting (20 trees, 80 cores) were cored at breast height

(1.3 m) for age determination and tree-ring width measure-

ment. The Bao Kaew and Nong Kra Ting sites were the same

as those for cambial activity analysis. All cores were glued

to wooden core mounts and surfaced with up to 400 grit

sand paper, in order to render the tree-ring boundaries more

clearly visible.

3.4. Meteorological data

Average monthly temperature and total monthly rainfall data

were available from both sites, Hung Bong and Nong Kra Ting.

Since there is no meteorological station at Bao Kaew, we used

the meteorological data from Hung Boung.

Monthly total rainfall from Om-Koi meteorological station

(about 40 km from Houng Boung and Bo Kaew and 30 km from

Nong Kra Ting) for the period 1977–2003 was used for the

dendroclimatological study. This period of 26 years, while

rather short for statistical comparison, was all that was available

for this study. Since the Om-Koi meteorological station does

not record temperatures, we used temperature data from Chiang

Mai, about 100 km east of the study area, available for the

period 1951–2003 (52 years).

N. Pumijumnong, T. Wanyaphet / Forest Ecology and Management 226 (2006) 279–289 281

Fig. 1. Three study sites and province boundary.

3.5. Chronology development

Ring-width measurements were carried out by using the

TSAP program (Rinn, 1986). A dating quality check was

done by the computer program COFECHA (Holmes

et al., 1986). Program ARSTAN (Cook, 1985) was applied

to detrend and autoregressively model the tree-ring width

series. Finally, the series were averaged for each site to


Fig. 2. Climate diagram of north Thailand; rainfall and temperature are recorded over 90 and 50 years, respectively.

obtain a master chronology using the robust mean

function.

4. Results

4.1. Seasonal cambial dynamics

The cambial development of both, the middle aged (PM1–

PM3) and the old aged (PM4–PM6) P. merkusii at Bao Kaew

are shown in Table 1. The cambium of all trees was still

dormant in March and April and included approximately 6.32

and 5.98 cell layers, respectively (Fig. 3a and b). With the

beginning of the rainy season in May the cambial activity

started, and in consequence the cambial zone widened,

reaching its peak in September with 10.20 cell layers

(Fig. 3c–h). Then the cambial activity of all trees declined

gradually toward the onset of the dry season. In the dormant

period it narrowed and consisted of thick-walled cells. In terms

Table 1

Cambial layers of middle aged/old aged P. merkusii from March 2000 to February

Month Average monthly

temperature (8C)

Total monthly

rainfall (mm)

March 24.09 115.6

April 24.90 165.8

May 24.69 534.7

June 24.07 302.6

July 23.95 91.1

August 24.38 249.7

September 24.06 450.5

October 24.31 280.6

November 20.82 3.0

December 20.32 107.0

January 20.83 0.3

February 21.79 0.0

of cambial activity, the middle aged trees revealed the same

pattern as the old aged ones. Only the number of cambial cell

layers was larger for the middle aged trees than for the old aged

ones, especially in the active season.

Our findings for the cambial activity of P. kesiya are listed

in Table 2. Again all trees were still dormant in March and

April (Fig. 4a and b) with a cambium width of 6.32 and 5.98

cells, respectively. By the onset of rain in May the cambium

of the young aged P. kesiya became active. The cambial

zone, together with the earlywood cells widened gradually

from May until a peak in October with 9.48 cell layers

(Fig. 4c–h). Then the number of cambial cell layers

decreased from November to February, which is the dry

season. In the middle aged trees the dormant period was

shorter than in the young aged trees. With the first rainfall in

May the cambial activity started and the cambial layers

increased up to a maximum in August. This was earlier than

in the young aged trees.

2001 and climatic data

Soil moisture

content (%)

Season Number of cells in the cambial

zone of middle/old aged trees

7.69 Dry 6.32 6.23

9.01 5.98 5.44

16.06 Wet 7.13 6.31

13.91 7.87 6.59

12.56 8.64 6.88

12.97 8.32 6.71

14.25 10.20 7.90

13.06 9.33 6.94

9.47 Dry 7.80 7.29

8.02 7.28 7.01

9.18 6.57 6.60

6.62 6.87 6.24


Fig. 3. The transverse sections of the middle age group of P. merkusii, showing seasonal cambial activity from March 2000 to February 2001; �625: (a) and (b)

dormant cambium (November–April); (c)–(h) active cambium of P. merkusii (May–October).


Table 2

Cambial layers of young aged/middle aged P. kesiya from March 2000 to February 2001 and climatic data

Month Average monthly

temperature (8C)

Total monthly

rainfall (mm)

Soil moisture

content (%)

Season Number of cells in the cambial

zone of young/old aged trees

March 21.90 95.88 9.88 Dry 6.32 5.40

April 24.60 110.84 12.44 5.98 5.38

May 24.50 287.8 20.75 Wet 7.65 6.28

June 24.70 141.44 19.45 7.88 6.56

July 24.60 178.84 18.58 8.51 7.26

August 24.90 120.36 16.69 8.45 7.82

September 25.10 148.24 19.28 8.79 7.76

October 24.15 217.60 19.98 9.48 7.23

November 19.00 0.0 12.64 Dry 7.51 7.09

December 18.55 31.96 9.26 6.81 6.25

January 18.45 0.0 7.25 6.54 5.75

February 19.55 0.0 9.05 7.16 5.51

To summarize, the trees of both pine species and of all age

classes were dormant until March and April. In all cases, it was

May rainfall that reactivated cambial divisions.

4.2. The relationship between cambial activity and climatic

variables

Table 3 illustrates the Pearson correlation between the

average number of cambial layers of the trees of both age

groups and the climatic variables as well as the intercorrela-

tion between the climatic variables. The average temperature,

e.g. has a significant positive relationship with rainfall and

tends to have a positive relationship with soil moisture.

Rainfall is significantly positively correlated with soil

moisture. Fig. 5 displays the connection between soil moisture

content, rainfall and cambial layers of the middle aged and the

old aged trees of P. merkusii over 12 months. The number of

cambial layers of the middle aged trees is significantly

positively correlated with soil moisture but not with to rainfall.

Although, the number of cambial layers of the old aged trees

showed a similar pattern, the correlation with soil moisture

and rainfall is insignificant.

During dormancy (November to April) rainfall at the Hung

Boung site in 2000–2001 was nearly zero in November (3 mm

of rain) and in January (0.3 mm); in February there was no rain

at all. However, rainfall was steady from March to June, then

dropped in July and increased again from August to the end of

October. The soil moisture content generally coincided with

the amount of rainfall, although it was never zero during the

observation year (see Table 1). Even if there is no rain,

moisture can still accumulate in the soil. Another considera-

tion supporting this conclusion is that the site of Hung Boung

is only slightly sloped (about 5–7%), at a high altitude

(1025 m above sea level) and its soil drains easily. In such

conditions, there are no climatic factors limiting pine growth.

It would be logical that growth is enhanced by increased

moisture available over a long portion of the year, particularly

during the dry months.

Regarding P. kesiya, high intercorrelations between rainfall,

temperature and soil moisture were found. The number of

cambial layers of the young aged and the middle aged trees

showed a highly positive relationship with soil moisture and in

tendency also with rainfall but with insignificant correlation

(Table 4 and Fig. 6).

4.3. Tree ring analysis

Tree-ring series are widely considered to be appropriate for

dendroclimatological studies if they have high values of mean

sensitivity and common variance in the first eigenvector, a high-

signal-to-noise ratio, and a low value of lag-1 autocorrelation

(Fritts, 1976). In Table 5 the statistics of the chronologies of the

three study sites are summarized; the chronologies are shown as

time series in Fig. 7.

In order to describe the climate–growth relationship, the

monthly rainfall and temperature from November prior to the

growing season to current October were correlated with the

so-called residual tree-ring chronology—that is the chronol-

ogy in which the autocorrelation has been eliminated by

autoregressive modeling (Fig. 8). At the HB site, the highest

positive correlation was with rainfall in May, which is the

beginning of the rainy season in Thailand, whereas tempera-

ture was not limiting growth (=no significant correlation); the

ring-width variation is climatically determined by 58.8%. At

the BK site, the highest positive correlation was with rainfall in

April, which is the transition from the dry to the wet season but

the trees responded positively to above-average rainfall nearly

throughout the entire period from November to July. At the

same time, the correlation with temperature is positive in from

November to July and negative during the whole period from

March to October; the ring-width variation is climatically

determined by 64.6%. At the NT site the highest positive

correlation was unexpectedly with rainfall in September and

with temperature in October, the ring-width variation is

climatically determined by 68.3%.

5. Discussion

Previous studies on the climate–growth response of pine

trees at various sites in Thailand had varying results. For


Fig. 4. The transverse sections of the young age group of P. kesiya, showing seasonal cambial activity from March 2000 to February 2001;�625: (a) and (b) dormant

cambium (November–April); (c)–(h) active cambium of P. kesiya (May–October).


Table 3

Correlation between climate variables and the number of cambial layers of P. merkusii (middle and old aged)

Climatic variable Temperature

(8C)

Rainfall

(mm)

Percentage of soil

moisture content

Cambial layers

(middle aged)

Cambial layers

(old aged)

Rainfall (mm) .634* –

Percentage of soil moisture content .542 .853** –

Cambial layers (middle aged) .173 .449 .623* –

Cambial layers (old aged) �.299 .173 .330 .820** –

* p < 0.05.** p < 0.01.

example, rainfall has been found to have a positive effect on

tree-ring width of P. kesiya in February and of P. merkusii in

April (Bamrungsak, 2003; Pumijumnong, 2004). Hutameta and

Pumijumnong (2003) found a positive correlation between

rainfall in March/April and tree-ring width of P. merkusii.

Buckley et al. (1995) and Boonchirdchoo (1996) investigated P.

merkusii and P. kesiya in Thung Salaeng Lung and Nam Nao

National Parks and showed a direct relationship with

temperature and an inverse relationship with rainfall at the

beginning of the wet season for P. merkusii. P. kesiya ring

widths showed a direct relationship to both temperature and

rainfall in September. Doungsathaporn (2000) examined the

effects of climate and of thinning on the growth of P. kesiya and

found that only rainfall in May had an effect on growth.

Sukkosol (1998) compared drought and flood events from Thai

historical documentary records with rainfall data and tree-ring

width of P. kesiya in Nam Nao and Phu Kradung National

Parks. Some tree rings in drought and flood years matched both

historical data and rainfall measurements.

It can be concluded that mostly P. merkusii has a

significantly positive relation with rainfall in the transition

period. Inversely, it has a significantly negative relation with

temperature in scattered months. P. kesiya, which has a shorter

life span than P. merkusii, often shows positive relations with

rainfall as well as with temperature in scattered months. The

most promising of these two species is P. merkusii, with a bit

stronger and obviously a significant response to climatic

variables. These results were confirmed by Buckley et al. (1995).

Fig. 5. Soil moisture (%) (dash line), rainfall (bar) and number of cambial layers of P.

Overall, the cambial activity of P. kesiya was considerably

more dependent on soil moisture than P. merkusii. A similar

study with P. kesiya, Khun Tan National Park, Lampang, by

Lerasamithra and Pumijumnong (2004) revealed a signifi-

cantly positive relation of cambial activity to rainfall and a

significantly negative relation to temperature; soil moisture

content was not included, because the study was conducted at

a high altitude on a steeply sloped terrain. Therefore, rainfall

was the main limiting factor for pine growth. In the current

study, the differences in the cambial activity between both

pine species and their responses to climatic variables

depended on the age of the trees, the variation in the

topography, and the soil type. The cambium of both pine

species became active in May and progressed through the

rainy season up to October and was dormant in the dry season

from November to April. These findings are similar to the

cambial development of teak in Northern Thailand (Pumi-

jumnong, 1997). The beginning of the monsoon is determin-

ing the growing season for teak and its cambial activity. The

cambial zone of teak widened from April to July, i.e. from the

end of the dry season through halfway the wet season.

Ingcachaichot (1984) suggested that the season of cambial

activity of Pterocarpus macrocarpus, Shorea roxburghii and

Dipterocarpus intricatus in Northeast Thailand, observed in

branches, was species-dependent and related to phenological

events. An investigation of the seasonal characteristics of

wood formation in Hopea odorata and Shorea henryana in

Eastern Thailand by Nobuchi et al. (1996), by mean of the

merkusii of the middle aged trees (solid line) and the old aged trees (dotted line).


Fig. 6. Soil moisture (%) (dash line), rainfall (bar) and number of cambial layers of P. kesiya of the young aged trees (solid line) and the middle aged trees (dotted line).

Table 5

Summary statistics of the tree-ring analysis

Sample

site

Tree

species

Time

span

Age range

(years)

Samples Statistics of the raw data Detrended series

Trees Cores Mean ring

width (mm)

Standard

deviation

(mm)

Auto

correlation

Mean

sensitivity

Signal-to-

noise ratio

Variance in

the first

eigenvector

(%)

Hung Boung (HB) P. merkusii 1855–2003 60–149 7 25 .32 0.11 .57 .32 1.68 27.77

Bao Kaew (BK) P. merkusii 1871–2003 54–133 8 21 .28 0.11 .63 .28 .81 22.04

Nong Kra Ting (NT) P. kesiya 1915–2003 29–89 20 75 .27 0.19 .67 .27 3.07 25.82

Table 4

Correlation between climate variables and the number of cambial layers of P. kesiya (young and middle aged)

Climatic variable Temperature

(8C)

Rainfall

(mm)

Percentage of soil

moisture content

Cambial layers

(young aged)

Cambial layers

(middle aged)

Rainfall (mm) .828** –

Percentage of soil moisture content .840** .870** –

Cambial layers (young aged) .520 .541 .789** –

Cambial layers (middle aged) .438 .347 .672** .871** –

** p < 0.01.

pinning method, revealed that the radial increment of both

species increased in the rainy season and decreased in the dry

season. Again, the degree of variation was dependent on the

tree species.

Tree-ring width is traditionally used to establish relation-

ships between tree growth and climate (Fritts, 1976). From the

response functions of the two pine species of the present study a

significant positive relation between the P. merkusii chronology

and rainfall in April and May was obvious. However, their

cambial activity has strong positive relations with soil moisture

but not with rainfall. Similarly, the cambial activity of P. kesiya

is strongly related to soil moisture. The difference between the

responses of cambial activity and tree-ring width to climate can

perhaps be due to the specific characteristics of the climate in

the observation year. The cambial activity was observed during

one year, whereas for the tree-ring width an average response

over 148 years was calculated.

However this study has demonstrated that environmental

factors, in particular soil moisture content and climatic data, are

important determiners of tree growth.

6. Conclusion

Our first attempt to evaluate the cambial activity of two

native pine species in Northern Thailand was successful. Pine is

a reliable recorder of rainfall in April and May and hence for the

onset of the monsoon. In the near future, it is urgently necessary

to sample old-growth pine trees in Thailand in order to get tree-

ring series extending back into the past as far as possible. With

such proxy data we want to contribute to the reconstruction of


Fig. 7. Pine tree-ring chronologies for (A) Hung Boung; (B) Bao Kaew; and (C) Nong Kra Ting.

Fig. 8. Climate–growth relationship between the pine indices and Om-Koi precipitation (left) and Chiang Mai temperature (right); correlation coefficient (bar),

response function coefficient (line); *p < 0.05: (A) Hung Boung; (B) Bao Kaew; (C) Nong Kra Ting; r2 = coefficient of determination.


the variability of the monsoon climate and thus to its better

understanding.

Acknowledgements

The research was funded by Thailand Research Fund grant

RSA4580035. We thank all members of forest stations for their

gracious help in collecting the data. We would also like to thank

Mr. Harry Toigo and Ms. Patcharin Pumchumnong for their

kind reading of the manuscript. Special thanks are owed to Prof.

Dr. Dieter Eckstein of the University of Hamburg for his strong

comments and suggestions. Finally, we thank anonymous

reviewers for reviewing of the manuscript.

References

Bamrungsak, J., 2003. Response of the tree rings of P. merkusii to climate: a

case study in Mae Hong Son Province, Supan Buri Province and Phechaburi

Province. M.Sc. thesis in Technology of Environmental Planning for Rural

Development, Faculty of Graduate Studies, Mahidol University (in Thai

with English abstract).

Boonchirdchoo, S., 1996. Correlative study of Pinus tree-ring width and

climatic variables. Case Study: Nam Nao and Phu Kradung National Parks,

Thailand. M.Sc. thesis in Technology of Environmental Management,

Faculty of Graduate Studies, Mahidol University.

Buckley, B., Barbetti, M., Watanasak, M., D’Arrigo, R., Boonchirdchoo, S.,

Suratanoon, S., 1995. Dendrochronological investigation in Thailand.

IAWA J. 16 (4), 393–409.

Cook, E.R., 1985. A time-series analysis approach to tree-ring standardization,

Ph.D. dissertation, University of Arizona, Tucson, AZ, USA.

D’Arrigo, R., Barbetti, M., Watanasak, M., Buckley, B., Krusic, P., Boonch-

irdchoo, S., Sarutanon, S., 1997. Progress in dendroclimatic studies of

Mountain pine in Northern Thailand. IAWA J. 18 (4), 433–444.

Doungsathaporn, K., 2000. Effect of climatic factors and thinning on growth of

Pinus kesiya Royle ex Gordon, at Bo Luang Plantation, Amphoe Hod,

Changwat Chiang Mai. M.Sc. thesis in Forestry, Faculty of Graduate

Studies, Kasetsart University (in Thai with English abstract).

Fritts, H.C., 1976. Tree Rings and Climate, second ed. Academic Press,

London.

Holmes, R.L., Adams, R.K., Fritts, H.C., 1986. Tree-ring chronologies of

Western North America: California, Eastern Oregon and Northern Great

Basin with procedures used in chronology development work including

users manual for computer program COFECHA and Arstan chronology

series. Laboratory of tree-ring research. University of Arizona, Tucson, AZ,

USA.

Hutameta, A., Pumijumnong, N., 2003. Pine tree-ring response to climate and

ENSO at Ban Wat Chan, Chiang Mai. Environ. Nat. Resour. J. 1 (2), 69–76.

Ingcachaichot, C., 1984. Seasonal variation of cambial activity of branch of

Pterocarpus macrocarpus, Shorea siamensis, Dipterocarpus intricatus.

M.Sc. thesis in Forestry, Faculty of Graduate Studies, Forestry: Kasetsart

University.

Lerasamithra, V., Pumijumnong, N., 2004. Seasonal variation of cambial

activity of Pinus kesiya in Doi Khuntan National Park, Lampang Province.

Environ. Nat. Resour. J. 2 (1), 1–10.

Nobuchi, T., Janmahasatien, S., Sakai, M., 1996. Seasonal changes of wood

formation and some characteristics of heartwood formation in Teak (Tec-

tona grandis L.) plantation. Kasetsart J. Nat. Sci. 30 (2), 254–263.

Pumijumnong, N., 1997. Cambium development of teak (Tectona grandis L.) in

Thailand and its relationship to climate.In: International Symposium on

Wood Science and Technology. Wood–Human–Environment, Seoul, Korea,

23–24 October 1997, pp. 61–72.

Pumijumnong, N., 2004. El Nino-Southern Oscillation (ENSO) in Thailand by

using tree-ring indices. National Research Council of Thailand, Bangkok,

Thailand (in Thai with English abstract).

Pumijumnong, N., Eckstein, D., Sass, U., 1995a. Tree-ring research on Tectona

grandis in Northern Thailand. IAWA J. 16 (4), 385–392.

Pumijumnong, N., Eckstein, D., Sass, U., 1995b. Reconstruction of rainfall in

northern Thailand from tree-ring series of teak. In: Proceedings of the

IGBP-PAGES/PEP II Symposium on Palaeoclimate and Environmental

Variability during the past 2000 Years in Austral-Asian Transect, Nagoya

University, Nagoya, Japan, 28 November–1 December 1995, pp. 186–191.

Rinn, F., 1986. TSAP. Time Series Analysis Program, Version 2.3. Reference

Manual. Heidelburg, Germany.

Sukkosol, V., 1998. A Study of drought and flood events in Thai historical data

of the 20th century and comparison with meteorological data and tree-ring

indices. M.Sc. thesis in Technology of Environmental Management, Faculty

of Graduate Studies, Mahidol University.

Seasonal cambial activity and tree-ring formation of Pinus merkusii and Pinus kesiya in Northern Thailand in dependence on climate

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