effect of tracked and rubber-tyred logging machines on soil … papers/pert vol. 14 (3... ·...

PERTANIKA 14(3), 265-276 (1991)

Effect of Tracked and Rubber-Tyred Logging Machines on Soil PhysicalProperties of the Berkelah Forest Reserve, Malaysia

KAMARUZAMANJUSOFFFaculty of Forestry

Universiti Pertanian Malaysia43400 UPM, Serdang, SelangorDarulEhsan, Malaysia.

Keywords: tracked, rubber-tyred, logging machine, forest soil.

ABSTRAK

Trafik jentera berat hutan beroda dan bertrek sedang menimbulkan prihatin terhadap mampatan tanah hutan.Berbandingdenganpertanian, mekanisasi hutan lebih berpontensi memusnahkanproduktiviti kawasan kerana mesin-mesin hutan adalah lebih berat dan operasinya dijalankan sepanjangtahun tidak kira keadaan cuaca. Ujianpadangkepadatan kenderaan mesin telah dijalankan dalam bulan keringdan basah (masing-masingjun dan November) diatas tanah lorn Hat di Hutan Simpan Berkelah, di Pahang Tengah, Malaysia. Penilaianpada duajenis mesin tanpamuatan (trektorrangkak danpemuat bertayargetah), duakandungan kelembapan tanah (14 dan 21 % keringoven)dan laluan kenderaan (0, 1, 2, 4, 8, 16, 32 dan 50 laluan)dijalankan pada kedalaman tanah dari 0 hingga 15 sm.Kadarkerosakan tanah amatlah berlainan di antara kedua-dua mesin. Perubahan ketumpatanpukalkering (DBD),jumlah ruangrongga (TPS), keronggaan udara (AP), muatanpegangan air bersedia ada (AWC), kekonduksianhidralik tepu (SHC) dan tahanan penembusan (RP) pada trektor bertayargetah tidak melebihi trektor rangkakjenistrek walaupun ada dua kaligandaperbedaan tekanan kontek bumi. Perubahan pada DBD dan TPS tanah disebabkanoleh kedua-dua mesin menaik dengan kenaikan kelembapan tanah. Walaubagaimanapun, perubahan pada AP,AWC, SHC dan RP menurun dengan kenaikan kandungan kelembapan tanah. Kebanyakan cirifizik tanah yangdikaji sampai ke maksima atau minima selepas dua trip yang pertama dan tidak berubah dengan trip tambahanselanjutnya dengan mesin bertayar. SHC didapati parameteryang paling sensitijuntuk perbedaan mesin. Kesanoperasi mesin berat di atas mampatanpermukaan tanah patut diiktirafdi dalam mekanisasi hutan.

ABSTRACT

Wheel and track traffic of heavy forest machinery is causing increased concern about forest soil compaction. Comparedto agriculture, forest mechanization is potentially more damaging to site productivity because forestry machines tend tobe heavier and operations are performed throughout the year regardless of weather conditions. Field experiments ofvehicular compaction tests were initiated in dry and wet months (June and November, respectively) on a clay loam soilat the Berkelah Forest Reserve in central Pahang, Malaysia. Two unloaded tree harvesting (TH) machine types (crawlertractor and rubber-tyred loader), two soil moisture contents (14 and 21 % of oven dry weight) and vehicular trips (0,1,2, 4, 8,16, 32 and 50 passes) were assessed on soil conditions from 0 to 15cmdepth. Rates of soil degradation are verydifferent for the two machines. Changes in soil dry bulk density (DBD), total pore space (TPS), aeration porosity (AP),available water-holding capacity (AWC), saturated hydraulic conductivity (SHC) and resistance to penetration (RP) ofthe rubber-tyred tractor did not exceed those caused by a track-type crawler tractor despite a two-fold difference in meanground contact pressure. The changes in soilDBD and TPS caused by both machines increased with increasing soilmoisture content. However, AP, AWC, SHC and RP decreased with increasing soil moisture content. Most soil physicalproperties studied reached a maximum or minimum after the first two passes and remained constant thereafter with thetyred machine. SHC appears to be the most sensitive parameter for machine differences. Effects of heavy machineryoperation on surface soil compaction should be recognized in forest mechanization.

INTRODUCTION preparation, planting and harvesting. The surface

Forest mechanization in Malaysia increasingly mineral horizons of undisturbed forest soils areinvolves the use of heavy mechinery for site sensitive to heavy machine traffic because of

•

KAMARUZAMAN JUSOFF

characteristically large (often greater then 60%)total porosities and low internal shear strengths.Kamaruzaman (1986; 1988) and Kamaruzamanand Nik Muhamad (1987a; 1987b and 1987c; 1988)observed that tree harvesting traffic reducedsaturated hydraulic conductivities, aerationporosities and increased bulk densities on tractorlogged-over and skid-road areas. Kamaruzamanet ai (1986) concluded that machinery trafficshould be concentrated on a minimum number ofskid roads to decrease soil erosion andsedimentation and to restore productivity.

Forest productivity can be decreased whenmachinery operations cause soil puddling, displace

surface soil, create ruts and compact soil. Of theseproblems, soil compaction maybe the most damag-ing because of the extent of the area affected andthe longevity of the effect. Compaction affectsyield adversely by decreasing height and diameterof trees because of restricted root elongation(Kamaruzaman 1988; 1989).

Forest soil compaction is widely recognized,but the extent is not well documented, particularlyin tropical forest operations. It is important toknow the effects of machinery upon soil conditionsand tree growth, to help managers choose themachinery and harvesting practices which are mostapplicable to optimize timber production. A ve-hicular compaction experiment was devised to

101°E 103°E

SOUTH CHINA SEA

SINGAPORE

Study area160 kn

) 0 3 " [

266

Fig. 1: Map of Peninsular Malaysia showing the study site

PERTANIKAVOL. 14NO.3,1991

EFFECT OF TRACKED AND RUBBER-TYRED LOGGING MACHINES ON SOIL PHYSICAL PROPERTIES

evaluate the effects of tree harvesting (TH) ma-chine type, on surface soil bulk density, porosity,water retention, resistance to penetration and satu-rated hydraulic conductivity.

MATERIALS AND METHODS

Study Area

Field experiments were initiated in June andNovember 1988 on a clay loam soil at the BerkelahForest Reserve in central Pahang, Malaysia (Fig. 1).The reserve is at 450 m above sea level, lies roughlybetween longitudes 102° and 103° East and latitudes4° and 5° North and is about 200 km north-east ofKuala Lumpur. Its area is about 121,400 ha and iscomposed of mixed hill dipterocarp forest Sloperanges from nearly level to 35°. Annual precipitationis approximately 2,100 mm, occurring mainlyduring April, May, November and December. Meanannual temperature ranges from 20 to 31°C. Theprincipal soil of the reserve is Durian Series (Ultisol).the surface texture of which ranges from sandyloam to clay loam.

MethodsBulk density, porosity, water retention, saturatedhydraulic conductivity and penetrometer resistancewere measured in the top 15 cm of the mineral soiltwo times with different soil water contents (14 and21% by weight), after various passes (0,1,2,4,8,16,32 and 50) by two machine types (a Caterpillar950B rubber-tyred grappler loader and a CaterpillarD6D crawler tractor). About 5 cm of organichorizon was removed from the soil surface beforethe measurements so that depth readings relatedonly to the mineral soil surface. The two differentsoil water content, 14% in June 1988 and 21% inNovember 1988 represented the extreme watercontents under which logging can occur.

The grappler loader (Plate 1) weighed 161,320N which was distributed over two axles and wasfitted with 20.5 - 25.20PR tubeless, nylon cord tyresinflated to 206 kPa. The ground contact area of thefour tyres was estimated at 1.09 m2 from data pro-vided by Tractors Malaysia Sendirian Berhad. Thecrawler (Plate 2) weighed 146,400 N and with 50.8x 237 cm tracks had a ground contact area of 2.4 m2.Unloaded static mean ground pressure for thetyred log loader and crawler tractor were 146 and60 kPa, respectively. Each machine, driven un-loaded at a constant speed of 3 km/h, was used tomake paths with 0, 1, 2, 4, 8, 16, 32, and 50 passes.

.*

Plate 1: The rubber-tyred grappler loader used for vehicularcompaction test

1n• A

2; The track-type tractor used for vehicular compaction test

The path length was 40 m with 1.9 m between paths.Samples of the surface mineral horizon were col-lected from each path. A fully randomised designwith 10 replications was used.

Ten undisturbed soil samples, 181 cm eachwere taken from 0 to 15 cm depth of the mineral soilwith a 1.95 cm diameter core sampler. Bulk density,porosity, water retention and saturated hydraulicconductivity were measured on each soil sample.The cores were soaked for at least 24 hours, after

PERTANIKAVOL. 14NO.3,1991 267

KAMARUZAMAN JUSOFF

which outflow measurements were initiated. Aconstant head of 14.0 cm of water was maintainedon the cores, and outflow rates were measured at aduration of 1,6 and 24 hours. The rate at 24 hourswas taken as a near steady state saturated hydraulicconductivity. Bulkdensitywasdetermined by dryingthe soil samples to a constant weight in a 105°Coven. Soil porosity and water retention character-istics were determined using a pressure chamberapparatus at matric potentials of-0.1, - 1 , -10, -33and -1,500 kPa. Air-filled porosity at 0.1 bar suc-tion, was calculated from the following relation-ship:

a

where,

- 8,-0,(0.1)

= macro porosity/air-filled porosity

= total pore space

.1) = percentage volume of water held at 0.1

bar suction

Saturated hydraulic conductivity was determinedon undisturbed cores. Penetrometer resistancewas measured using an ELE model EL510-030pocket penetrometer with a stainless steel plungerand a tip area of 0.2 cm . A total of 10 readings wasmade per trip per treatment.

RESULTS AND DISCUSSIONBulk DensityIn the surface soil with 14 and 21 % moisture contentthe soil bulk density increased sharply after the firsttwo trips or passes of the tyred loader, after whichfurther trips brought about smaller increases (Fig.2). There were significant differences in bulkdensity between 0 and 2, 4, 8, 16, 32, 50 passes atboth moisture levels for both machines. Each

1.72

M.C. RUBBER-TYRED LOGGING MACHINE

D Q21Z M.C. RUBBER-TYRED LOCCINC MACHINE

: M.C, TRACK-TYPE LOCCINC MACHINE

M.C, TRACK-TYPE LOCCINC MACHINE

J I I L J 1 I L.

0 2 U 6 8 10 12 16 16 18 20

NUMBER OF MACHINE TRIPS

^ ?fc 28 30 32 50

Fig. 2: Bulk density of the surface soil as affected by machine type, number of passes and moisture contents

268 PERTANIKAVOL. 14NO.3,1991

EFFECT OF TRACKED AND RUBBER-T\KED LOGGING MACHINES ON SOIL PH\SICAL PROPERTIES

Ul

UU

42

w 41u< ,oMUS 39

37

30

35

34

N

zM.C, RUBBER-TTRED LOCCINC MACHINE

O O 2 1 T M.C, RUBBER-TTRED LOCCINC MACHINE

%- -%\kX M.C, TRACK-TYPE LOCCINC MACHINE

M.C, TRACK-TYPE LOCCINC MACHINE

I t i I I I | L I _ i 1 f\—10 12 U 16 18 20 22 24 26 28 30 32 50

NUMBER Of MACHINE TRIPS

Fig. 3: Total porosity of the surface soil as affected by machine types, number of passes and moisture contents.

machine compacted the soil to a different extentprobably because of differences in contact pressure.Interactions occurred between machine type andmoisture level or between machine type and numberof passes. The two logging machines had differenteffects on levels of moisture and machine passes.

The bulk density of soil gradually increasedwith successive passes (Fig. 2); by the 32nd pass, ithad reached 1.60 g/cm3. The equation BD = a + blog T, where BD = soil bulk density, a = bulk densityintercept and T = the number of the vehicularpasses, applies to a quasi-linear segment of the datarange for the rubber-tyred vehicle. For the trackedvehicle, a square root relationship gives a better fitto the data range, except for very low values of T.For all data, both the logarithmic and square rootequations were highly significant (P < 0.05). Thelogarithmic relationship between compaction and

number of machine passess for the rubber-tyredvehicle is not similar to those reported by otherresearchers. The dissimilarity in the functionalrelationship of compaction would seem to bestrongly influenced by machine characteristics aswell as the differences in soil organic matter con-tent, soil moisture content, soil texture and struc-ture, soil strength and surface litter depth of tropi-cal hill forest soils.

PorosityThe two machines produced significant differencesin mean total soil porosity and air capacity (Table1), but these were not changed by the difference insoil moisture content; the total porosity of soil at14% moisture was always about 2% greater for bothmachines than at 21% moisture (Table 1). Similarly,the air capacity at 14% moisture level was 7%greater than at 21% moisture (Figs. 3 and 4). The


KAMARUZAMAN JUSOFF

TABLE 1The main effect of two types of logging machines tyre configuration on some selected soil physical

properties of the upper 15 cm depth

rn 111 Kir

NUMBER B.D

01

248

163250

(g/cm3)

14% 21%MC

1.40a1

1.42a1.45b1.48b

11.51b1.54b1.60b1.61b

MC

L42aL.43aL46bL49bL53bL57b1.65b1.66b

T.P.S

(%)

14%MC

47.32a46.38a45.44b44.26b42.98b41.74b39.59b39.43b

CAT D60 CRAWLER TRACTOR

21%MC

46.34a46.08a45.06b43.70b42.45b40.90b37.89b37.32b

A.P

(%)

14%MC

18.56a17.54a15.76b14.61b13.83b12.07b9.83b8.91b

21%MC

17.39a16.80a14.72b13.75b12.97b11.37b8.42b.7.48b

AWC(mm/m)

14%MC

109.8a107.1a106.3b104.1b102.9b99.1b87.9b86.5b

21%MC

106.4a103.6a101.1b99.2b98.3b96.5b85.9b83.2b

SHC(cm/hr)

14%MC

77.0961.95c51.31d40.69d94.07d21.36b5.68d4.45d

21%MC

67.80c53.47c41.76d29.93d19.42d12.16d4.60d3.87d

RP(kPa)

14% 21%MC MC

205.95a 156.91a245.18a 166.72274.60b 186.33b294.21b 215.75b323.67b 235.37b362.86b 254.98b421.70b 264.79b431.51b 264.79b

Mean 1.502 1.53a 34.39a 42.47a 13.89a 12.91a 100.5a 96.8a 37.08c 29.13c 319.96a 218.21a

StandardDeviation 0.08 0.09 2.98 3.51 3.46 3.53 8.8 6.2 25.03 23.51 81.03 43.78

C.V(%) 5.3 5.9 8.7 24.9 27.4 88.8 6.4 67.5 80.7 25.3 20.1

CAT 9508 GRAPPLER LOADER

NUMBER B.D

01248

163250

Mean

(g/cm

14%MC

1.40a1

L44a1.50b1.64b1.65b1.56b1.67b1.68b

1.58a2

StandardDeviation 0.10

C.V(%) 6.3

3)

21%MC

L43a1.47a1.52b1.66b1.67b1.68b1.59b1.70b

1.62a

0.11

6.8

T.P.S(%)

14%MC

47.32a45.77a39.47b38.19b37.62b37.52b36.94b36.45b

39.88a

4.23

10.6

21%MC

46.11a44.68a38.98b37.28b37.10b36.79b36.11b35.70b

39.09a

4.03

10.3

A.P

<%)

14%MC

17.64a15.06a12.36b11.25b9.83b9.72b9.39b9.12b

11.67a :

3.13

26.8

21%MC

15.53a13.43a11.58b9.78b9.58b9.42b8.83b8.23b

L0.80a

2.53

23.4

AWC(mm/m)

14%MC

105.70a104.2a99.7b98.7b97.5b96.0b95.3b94.3b

99.1a

4.4

4.4

21%MC

100.2a97.3a96.7b97.0b94.1b93.6b92.2b90.0b

95.1a

3.3

3.5

SHC(cm/hr)

14%MC

76.30b30.11b4.79c2.68c2.53c2.25c1.97c1.97c

15.30b

24.47

160.0

21%MC

64.40b42.71b3.28c1.80c1.71c1.63c1.57c1.47c

14.82b

24.61

166.0

RP(kPa)

14%MC

196.14a245.18a304.02a392.28b402.09b411.89b431.51b441.32b

383.05a

92.59

24.2

21%MC

166.72a186.33a205.95a254.98b294.21b304.02b313.82b313.82b

254.98a

60.68

23.8

270 PERTANIKAVOL. 14NO.3,1991


H.C, RUBBER-TYRF-D LOCCINC MACHINE

D O217. M.C, RUBBER-TtRED LOCCINC MACHINE

-»!<.?. M.C. TRACK-l^PE LOCCINC MACHINE

•*!* M.C, TRACK-TYPE LOGGING MACHINE

10 12 U 16 18 ?0 2? ?u ?b 28 30 32


Fig. 4: Aeration porosity of the surface soil as affected by machine types, number of machine passes and moisture contents.

decrease in air-filled pore space results from closure.This also dimishes the amount of water available fortree growth (Table 1).

Moisture ContentFor the drier soil (14% moisture), there was littledifference in bulk density between the rubber-tyred loader and track-type tractor. Thus, thechanges in bulk density for both soils under wheeland track reflect the general differences insoil water content at the time of passes as shown inthe water retention (pF) curves (Figs. 5 and 6).High relative susceptibility of hill forest soil tocompaction is found in wetter soils for bothmachines.

Saturated Hydraulic ConductivityFig. 7 shows the changes in near steady-statesaturated hydraulic conductivity of topsoil at twomoisture contents after increasing passes by both

machines. The rubber-tyred loader significantlydecreased the hydraulic conductivity by about 98%,and the tracked tractor decreased it by 94% after 50passes. Saturated hydraulic conductivity wasdecreased by more than 60% after one pass withthe rubber-tyred loader but only after 16 passeswith the crawler tractor (Fig. 7). Differences inmoisture content made little difference in hydraulicconductivity after compaction by either machine(Table 1).

Fig. 8 shows a linear relationship (P<0.05)between decreasing hydraulic conductivity andincreasing bulk density for data pooled across alltreatments with rubber-tyred and tracked machinesat 14% moisture content. The observations fromthis study would reliably predict the decreases insaturated hydraulic conductivity and air capacity orincreases in bulk density.


KAMARUZAMAN JUSOFF

150Q I

33

10

1.00.1

0

•

Q

•

A

0

1

2

4

B16

32

50

14%

21*

TRIP

TRiP

TRIPS

TRIPS

TRIPS

TRIPS

TRIPS

TRIPS

M.C

Vf.C

10 20 30 40 50

WATER CONTENT (% V/V)

60 70

Fig 5: The effect of the number of track-type logging machine passes on soil-water retention at two moisture levels

Penetrometer Resistance

Fig. 9 shows mean penetrometer resistance ofsurface soils measured before and after vehicularpasses by both machine types and in both moistureconditions. Both the rubber-tyred and trackedmachines significantly increased the penetrationresistance of the surface 15 cm (P < 0.05); theresistance caused by the wheeled machine wassometimes 40% more than that caused by thetracked machine. Because of the compact soilconditions, data could not be obtained above theupper limit of the penetrometer (440 kPa) for 32 or

more passes. Penetration resistance valuesincreased sharply in dry soil for the wheeled machineeven after two passes. The increase was, however,m'ore gradual for the tracked machine. Thisdifference can be attributed to the differences inground contact pressures between the machinesand not their total weights. For both machines,penetrometer resistances changed less in the wettersoil then in drier soil probably due to the lowercompaction effort in wetter soil. The rapid increasein penetrometer resistance caused by the wheeledmachine on the drier soil, up to about 430 kPa cone

272 PERTANIKAVOL. 14NO.3, 1991


500 I " " * •

33

10

1.00.1

—

\ \ \\i111

I

1w\\1

1

ti1J;II

) 1

lMl'1 M\\ V M

1u\V«lmll\\

II

1

1

O

•

o•

•

—

. . . .

0 TRIP

1 TRIP

1 TRIPS

4 TRIPS

8 TRIPS

16 TRIPS

32 TRIPS

50 TRIPS

14% M.C

21% M.C

10 20 30 40

WATER CONTENT i% V/V)

50 60 70

Fig. 6: The effect of the number of rubber-tyred logging machine passes on soil-water retention at two moisture content levels

resistance after 16 passes is likely to limit rootgrowth.

CONCLUSION

The greater contact pressure of the wheeledmachine resulted in greater changes in soil densityand porosity than with the tracked machine. Boththese soil properties were greatly affected by bothmachines at 14 at 21 % moisture contents. Both soilmoisture content and the number of machinepasses significantly affected the extent to whichthese soil properties were changed in the 0-15 cm

layer. An important consequence of this topsoilcompaction is the decrease in hydraulicconductivity. This is likely to be detrimental to treegrowth but some benefits may also be realized,because under dry conditions, decreasedconductivity may conserve soil water. Traffic withrubber-tyred logging machines should beconcentrated on a minimum number of skid tracksto decrease the extent of severe soil disturbancethey can cause, so that treatment to restoreproductivity is limited to a small area.

The vehicular compaction test showed that


KAMARUZAMAN JUSOFF

• nO----0» •

o -o

to .

| l X

I4X

2\%

M

n

M

M

.c .

.c.

.c,

.C,

RUB8ER-TIRE0 L0CC1NC MACHINE

RUBBER-TIRED LOCCINC MACHINE

TRACK-TYPE L0CC1NC MACHINE

TRACK-TYPE LOCC1HC MACHINE

10 12 U 16 IB 20


22 24 32 50

Fig. 7: Saturated hydraulic conductivity of the surface soils as affected by machine type, number of machine passes and moisture content

water content and compactive effort (machinepasses) interact and that this interaction must beconsidered by forest managers when predictinghow soils will react to machine passes. Restrictingoperations with wheeled machines during wet

periods when soil water content is high wouldobviously decrease the possibility of soil damage bycompaction. Since logging contractors can illafford to stop their operations due to the constantdemand for logs by the sawmills, research is



E l - 7 6

IB

17

16

15

U

13

12

~ H9k

1 10M

6 'M2 8

I 6•

5

4

3

2

1

m

1

-V

- *Y y

/ \ \D \ \: V\

--• 1 1 1 1

• • A,

D-OA

O--OB

SN

V

1 1 1

a

r,D,

r,D,

RUBBER-TIRED LOCC1NC MACHINE

RUBBER-TIRED LOCC1HC MACHINE

TRACK-TYPE LOCC1NG MACHINE

TRACK-TVPE LOGGING MACHINE

m

-

-

-

s.

i i i i i i l \ i

10 15 2 0 25 30 35 40 45 5 0 55 60 65 7 5

SATURATED HYDRAULIC CONDUCTIVITY (CM/HR)

I . 7 4

1.72

1.70

1.68

1.66

1.64 w

1.6? S

i.6o q

|1 .^8 ^

1.56 " *

1 . 5 4 ^

1-52

I .50

1.48

1 .46

1.40

Fig. 8: Relationship between air capacity, bulk density and saturated hydraulic conductivity of track-type and rubber-tyred loggingmachine at 14% moisture content level

required to develop the design of tyre configura-tion of the machines.

REFERENCES

KAMARUZAMAN JUSOFF. 1986. Off-and-on RoadTransportation Machines: Their PossibleApplications in the Upland Forest of Malaysia.Occasional Paper No. 8, Faculty of Forestry,Universiti Pertanian Malaysia, Serdang, 27 p.

KAMARUZAMAN JUSOFF. 1988. Soil Compaction fromOff-road Transportation Machine on Hill ForestLand. Pertanika 11(1): 31-37.

KAMARUZAMAN JUSOFF. 1988. Height and DiameterGrowth of Acacia mangium Seedlings in CompactedSoils. Poster/paper presented at the International

Symp. on Forest Tree Physiology, September 25-30,Nancy, France.

KAMARUZAMAN JUSOFF. 1989. The Initial Establishmentand Growth of Acacia mangium Seedings onCompacted Soils. Paper presented in IUFRO Div.3 symp. Efficiency of Stand Establishment Operation, 11-15 September 1989, Rimu Room, FRI, Rotorua,New Zealand.

KAMARUZAMANjUSOFFandNlKMUHAMADMAJID. 1987a.The Effects of Clearing and Continuous Cultivationon the Physical Properties of Upland Forest Soils.In Proc. Impact of Man's Activities on Tropical UplandForest Ecosystem ed. Yusof Hadi, Kamis Awang, NikMuhamad Majid and Shukri Mohamed p 217-237Faculty of Forestry, Universiti Pertanian Malaysia.3-6 February, 1986, Serdang, Malaysia.

PERTANIKA VOL. 14NO.3, 1991 275

KAMARUZAMAN JUSOFF

o

I5

u

\U7. M.C, RUBBER-TYRED LOCCINC MACHINE

O O 2 U N.C, RUBBER-TYRED LOCCINC MACHINE

•—• •« \U7. N.C, TRACK-TYPF LOCCINC MACHINE

*- — -* 21Z N.C, TRACK-TYPE LOGGING MACHINE

0[-

I j L I I _L0 2 10 12 14 16 18 20 22 24 26 28 30 32


•\-i50

Fig. 9: Resistance to penetration of the surface soil as affected by machine type, number of machine passes and moisture contents

KAMARUZAMANJUSOFF and NIK MUHAMAD MAJID. 1987b.

Impacts of Deforestation on Soil PhysicalCharacteristics in Steepland Forest. Paperpresented at the International Conference on SteeplandAgriculture in the Humid Tropics, 17-21 August, 1987.Kuala Lumpur, Malaysia.

KAMARUZAMANJUSOFF and NIK MUHAMAD MAJID. 1987C.

Effects of Crawler Tractor Logging on SoilCompaction in Central Pahang. Paper presented atthe UNESCO/IHP Workshop on Impacts ofOperations in Natural Plantation Forests on Conservationof Soil and Water Resources, 23 June - 1 July, 1987.Universiti Pertanian Malaysia, Serdang, Selangor,Malaysia.

KAMARUZAMANJUSOFF and NIK MUHAMAD MAJID. 1988.

Effects of Site Preparation Methods on Soil Physical

Characteristics. In Proc. of 5th. International SoilConservation Conference, ed S. Rimwanich p 745-754

January 17-30, Bangkok, Thailand.

KAMARUZAMANJUSOFF, NIK MUHAMAD MAJID and DESA

AHMAD. 1986. Effects of Logging Roads on Erosionand Sedimentation. In Proc. Workshop on Roadingand Development Activities in Relation to Soil Erosionand Sedimentation Control in Watersheds, ed. S.R.Saplaco, E.M. Baltazar. p 43-55. July 20-26. Jakarta,Indonesia.

(Received 21 May, 1990)


effect of tracked and rubber-tyred logging machines on soil … papers/pert vol. 14 (3... ·...

Documents