CANADA

Department of Forestry

ROOTING HABITS OF WHITE AND RED PINE

97659-7-1

by

W. G. E. Brown and D. S. Lacate

Forest Research Branch Technical Note No. 108

1961

Published under the authority of

The Honourable Hu�h John Flemming, P.C., M.P.,

Minister of Forestry

Ottawa, 1961

ROGER DUHA�1EL, F.R.S.C.

QUEEN'S PRINTER AND CONTROLLER OF STATIONERY

OTTAWA, 1961

Cat. No. Fo 47-108

CONTENTS

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

PAGE

5

METHODS. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Tree Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Excavation and Recording of Roots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

RESULTS... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Root Form..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 6 Lateral Rooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Vertical Rooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Responses to Soil Moisture, Texture and Structure . . . . . . . . . . . . . . . . . 7

SUMMARy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

APPENDIX-Root Systems Arranged by Soil Moisture, Soil Texture,

97659-7-1!

and Parent Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Rooting Habits of White and Red Pine by

W. G. E. Brown1 and D. S. Lacate2

INTRODUCTION

The fieldwork on which this report is based was carried out at the Petawawa Forest Experiment Station between 1954 and 1955. During this period the roots of a limited number of comparable specimens of red pine (Pinus resinosa Ait.) and white pine (Pinus strobus L.), selected to represent a range of contrasting conditions, were excavated.

The main objectives of this investigation were (1) a comparison of the root systems of the two species where they occurred together on a variety of soil conditions, and (2) a study of the relationships between the form of the root systems of mature trees anu the soils in which they grew. This information can be useful in the appraisal of performance characteristics of each species on a variety of soil and site conditions.

METHODS Tree Selection

Because of the time and labour involved in root excavation it was necessary to restrict the sample to a few carefully selected specimens. The site criteria emphasized were parent material, soil texture, and soil moisture regime as outlined by Hills (1950). Classes of soils included coarse gravel outwash, sandy to sandy loam materials of outwash, aeolian and ponded (lacustrine) origins, and compact glacial till. Somewhat dry to moist soil moisture classes were sampled.

On each of the various sites located in natural stand conditions a repre­sentative red pine and white pine were selected for excavation. Only dominant and co-dominant trees, at least 10 feet distant from any other sizeable tree in the stand, were used. The majority were in the same age class-50 to 80 years­although several were in the 80-100 year age class.

Excavation and Recording of Roots Root excavation procedures were similar to those outlined by Lutz et al.

(1937). A trench 10 feet long and at least two feet wide was dug tangential to the bole to bisect the root system. The inner face of the trench was within 12 to 24 inches of the outer margin of the tree bole. Excavation was done manually using a shovel, trowel, and saw. Roots encountered that were more than! inch in diameter were removed from the trench after a plan view of their location was sketched. The trench was deepened to at least six inches below the general level of the root system to provide a clean cross-section of vertical rooting pat­terns. The morphological characteristics of the soil profile were described in detail at this stage.

To facilitate accurate sketching, a one-foot grid of cord attached to spikes was superimposed on the exposed profile face. Root ends, their size and position on the profile, were plotted on graph paper. Following this the vertical root

1 Forester and Soils Specialist, formerly with the Forestry Branch, Department of Northern Affairs and National Resources.

, Research Officer, Forest Research Branch, B.C. District Office, Victoria, B.C.

5

system was unearthed, commencing at the base of the pit and progressing upward and inward until the main system was exposed in its natural position. This procedure resulted in a minimum of breakage of smaller roots. The exposed roots were then drawn on the profile sketch.

Two or three surface laterals approximately 90 degrees from each other were also unearthed and sketched in plan view on another sheet of graph paper. Roots that suddenly dipped into the ground were not followed but were noted as "sinkers".

The following terminology was used to describe various types of roots exposed during excavation:

(1) Taproots

(2) Surface laterals (3) Lateral sinkers (roots that dip down and which originate on surface

laterals)

(4) Central sinkers (sinkers originating from the main bole)

(5) Fine roots-fan-shaped or brush-like formations,

-short, thickened roots,

-dead roots. The depth to water table (if present) and the maximum depth to which

roots penetrated were noted in each trench. Additional characteristics of the root system were also recorded, e.g., frequency and pattern of forking.

RESULTS

The root systems sampled are shown in the appended diagrams, arranged to facilitate comparison of species and of conditions. Only the vertical systems together with soil profile descriptions have been illustrated. The latcral systems as sketched in the field did not differ enough to warrant graphic comparison; their characteristics are dealt with in the text.

An over-all comparison of root development according to species, soil moisture, texture and material is shown in Nos. 1 to 10. Certain special character­istics of root distribution in relation to soil profile features are illustrated in Nos. 11 to 14. An estimate of the relative performance of each species on each location was obtained by comparing site index of the sample trees with site index curves presented by McCormaek (1956) in his report on growth and yield of red and white pine stands of Ontario and Quebec.

Root Form

Although on a few specific soils there is some dissimilarity, the rooting habits of both species were found to be quite similar on the majority of locations sampled. During the first few years young pines of both species usually develop a taproot and numerous branched laterals. The taproot is more often retained in red pine than in white pine, although this characteristic is largely influenced by soil conditions. In general the root system of white pine has a wider spread of laterals. Both root systems are capable of penetrating deeply into the subsoil, and of developing numerous central and lateral sinkers under favourable conditions.

Lateral Rooting

The lateral roots of both species are generally large and often are only a few inches below the ground surface. Smaller vertical roots or sinkers descend from these. If unhindered by competition from neighbouring trees, the longest laterals may extend beyond the limits of the crown and attain a length roughly comparable to the height of the trec. The lateral roots of white pine seem to be

6

more extensive than those of red pine; the longest white pine lateral recorded was 60 feet, whereas the longest red pine lateral was 40 feet in length. Fine roots develop along the length of the main laterals in both species. These are usually concentrated within the top foot of soil.

Vertical Rooting,

Both central and lateral sinkers were found to occur in each species but these were notably better developed and more abundant in white pine, pre­sumably supplanting a taproot. In both species vertical roots on occasion pene­trated to 15 feet. It is probable that they may extend even deeper into soils which are exceptionally loose and well-drained.

The taproot and sinkers of red pine, on contact with impenetrable material or rock fragments, follow closely along the surface of the obstruction and turn downwards at the first opportunity (see Nos. 5 and 13). On the other hand there are indications that white pine roots spread out horizontally on reaching such materials. As an example, where bedrock was found not far below the surface it was observed that red pine roots were mostly confined to the crevices, whereas white pine roots were spreading laterally to local favourable conditions. These differences may explain the superior growth of white pine on shallow soils having deeper pockets scattered throughout, and may also point to the reasons for the greater persistence, in a stunted form, of red pine on knolls of deeply fractured bedrock.

Responses to Soil Moisture, Texture and Structure

Wet soils are not conducive to development of healthy roots in either species as witnessed by the frequency of short, thickened root tips in gley horizons and at the upper surfaces of compact soil materials. Fine roots and root tips of red pine located in gley horizons are frequently dead. Live roots of white pine, however, are often found at greater depths in poorly aerated gleyed zones. On sites having a high water table the root systems of white pine consist almost entirely of lateral branches which form a shallow plate-like mass. The poor performance characteristics of red pine on such wet areas may be a result of its less flexible rooting habits and restricted lateral root development.

Sandy soils with thin strata of moderately fine material at a depth of two to four feet are highly productive, favouring the development of stratified masses of fine roots just above and sometimes below the finer-textured soil layers. (Note Nos. 11 and 12.) Loose-structured sandy soils, as found in dunes, can also be highly productive except under conditions of very excessive soil drainage. These soils permit the development of exceptionally vigorous, extensive root systems with sinkers penetrating deeply into the subsoil (see Nos. 3 and 4). Both species of pine have deep rooting in soils devoid of inhibiting strata, and hence can be considered relatively windfirm.

Productivity decreases wherever restrictions in development of root systems occur-where a hardpan or gley stratum approaches the surface, and where dry, very coarse, compacted materials are present. The latter prevent easy penetration of the normally thick pine roots and a stunted root system develops (Nos. 1 and 2).

SUMMARY

Rooting habits of white pine and red pine are quite similar on the sites studied, although red pine maintain a taproot more consistently. Extensive development of sinkers is common in each species. Deep rooting is evident in the root systems of both but lateral root development is more extensive in white pine. Soil conditions such as a high water table, a pan, or a coarse gravel horizon restrict rooting and decrease performance accordingly. Extensive, vigorous root systems with corresponding high productivity occur on fine sandy soils of ponded and aeolian origin.

7

Literature Cited

HILLS, G. A. 1950. The use of aerial photography in mapping soil sites. For. Chron. 26(1).

LUTZ, H. J., J. B. ELY and S. LITTLE. 1937. The influence of soil profile horizons on root distri­bution of white pine. School of Forestry Bull. 44, Yale University, New Haven, Conn.

MCCORMACK, R. J. 1956. Growth and yield of red and white pine. Canada, Dept. Northern Affairs and National Resources, Forestry Branch, S and M 56-5.

8

•

APPENDIX

Root Systems

Arran�ed by Soil Moisture, Soil Texture, and Parent Materials

9

VERY DRY - COARSE

RED PINE No.1

•

- WELL DEVELOPED TAPROOT, BENT IN GRAVELLY C HORIZON.

- FINE ROOTS AND SINKERS FEW IN NUMBER.

- LATERALS NEAR SURFACE, EXTENDING TO 35 FT., ARE

MAIN SU PPLIERS.

WHITE PINE

No.2

- NO TAPROOT. - CENTRAL SINKERS NOT LARGE, FINE ROOTS NOT NUMEROUS. - LATERALS NEAR SURFACE, EXTENDING TO 35 FT., ARE MAIN SUPPLIERS.

10

Loamy sand

and �rovel

C Outwash CjIrovel

SITE Ill: TOTAL A G E -70 HEIGHT -28

Gravelly B loom

Oulwosh C gravel

SITE IT T OTAL AGE - 80 HEIGHT - 56

3

4

2

[ 3

1\

5

SOMEWHAT DRY - COARSE TO MEDIUM

- WELL DEVELOPED T APROOT; NUMEROUS SINKERS DESCEND TO 12 FT. - FINE ROOTS FAN FREQUENTLY THROUGHOUT B AND C HORIZONS. - L ATERALS IN B EXTEND TO 35 FT.

WHITE PINE

- NO DEFINITE TAPROOT, BUT NUMEROUS CENTRAL SINKERS DESCENDING TO 10 FT. ARE PRESENT.

- FINE ROOT FANS ABUNDANT T HROUGHOUT B AND C HORIZONS. -- LATERALS IN B EXTEND TO 35 FT.

Aeolian fine

loamy sand

B Medium and

fine sand,

Ponded and bonded

C

SITEr TOTAL AGE-72

B

C

HEIGHT -74

Aeolian loamy sand

Aeolian

medium and fine loamy

sand

Medium and

fine sand,

Ponded and

bonded

SITE I TOTAL AGE - 64 HEIGHT - 72

2

3

[ 4

6

2

3

� 4

5

6

FRESH - MEDIUM TEXTURED

RED PINE

NO.5

- - --�---&'-� -:�--Pc ;lI'fI I/-k'�,-=--=--f:::: Ao

Aeolian A2

.. :--.....�--'----

- NO OEFINIT E TAPROOT, B UT MANY CENTRAL SINKERS ARE PRESENT WHICH FORK FREQ UENTLY AT CONTACT WITH STONES.

- MAN Y FINE ROOTS IN LOWER B AND C HORIZONS. - LATERALS EXTEND 15 FEET AND THEN BECOME SINKERS.

WHITE PINE

- NO TAPROOT, B U T MANY WELL DEVELOPED SINKERS PRESENT. - LAT ERALS EXTEND 20 FEET THEN BECOME SINKERS.

12

C

Medium and fine sand

Loamy medium sand

Stony medium sand

Moulded till

loamy sand

to

sandy loom. stony

SITE II TOTAL AGE -75 HEIGHT -72

Loamy sand

Loamy sand

(Ae olian

B cop)

Medium sand

C Fine loamy

sand

Moulded ti II, o stony sandy

3

4

2

3

4

loom, compact 5

SITEI TOTAL AGE - 70 HEIGHT -80

[

SOMEWHAT MOIST - COARSE TO MEDIUM

RED PINE

NO.7

- WE LL OE V E LOPED TAPROOT AND A FEW CE NTRAL SINKERS PRE SE NT, ALL E NDING ABRUPTLY AT GLE Y E D ZONE.

- MANY DE AD, T H ICKE NE D ROOT S PRESENT. - LATERALS E XT E ND 15 FE E T THEN DIP ABRUPTLY .

C

G

Aeolian over

woterlaid sands

Loamy sand

Medium sand

Medium sand slightly gleyed

Lo amy sand

Iron p an

F ine sandy loom. compact

SIT E I TOTAL AGE -75 HE IGHT -78

2[

3

4

r-_____________________ �W�H�IT�E�P�IN:� E ______________________ � NO.8

- NO TAPROOT, MODE RATE DE VE LOPME NT OF CE NTRAL AND LATE RAL SINKERS, MANY THICK E N E D AND DE AD IN GLE YED ZONE.

- MODE RATE CONCE N TRATION OF FINE ROOTS IN B. - LATE RALS E XT E N D TO 40 FT. FROM TRE E .

]3

Aeolian over woterloid

sands

__ ___ }A2 Lo amy sand

Lo amy sand _0 . B

- 0 - -Medium sand

--Medium s and,

C s lig htly g leyed

G

M��it��at� ad

nd 1 Stratified

Iron pon

Fine lo amy sand

SITE I TOTAL AGE - 80 HE IGHT - 83

3

4

MOIST - COARSE RED PINE

�.9

- NO TAPROOT, 8RUSH TYPE SINKERS ARE STUNTED AND DEAD AT STRONGLY GLE YED ZONE.

- LATERALS MODERATELY WELL DEVELOPED IN 8 HORIZON.

WHITE PINE

Outwash

Loamy

sand

8 Loamy

sand, mottled

Medium sand. C slightly

gleyed

G Coarse

sand

SITE m TOTAL AGE - 100 HEIGHT - 68

Outwos material

------------ Ao

-----�A2

- NO TAPROOT; BRUSH TYPE SINKERS END IN THICKENED AND DEAD ROOTLETS IN STRONGLY GLEYED ZONE.

- LATERALS WELL DEVELOPED IN B WITH N UMEROUS FINE ROOTS BEING PRESENT.

14

8

Sandy

loam

Medium and

fine sand

Medium and fine sand,

mottled

Medium and C fine sand I

mottled

Medium and G fine sand

SITE IT TOTAL AGE -90 HEIGHT -84

2' ;> !l

3

4

2

4

5

ROOT SYSTEMS SHOWING SPECIAL SOIL EFFECTS­INTERBANDED, MEDIUM TEXTURED SOILS,

FRESH MOISTURE REGIME

RED PINE

No.11 Aeolion over ponded sands

---------Ao

� ,,-----==���:j:���:'��� ��\�\'- - ----- - - - Iron pan, very 2

tine sa ndy loa m [

Fine sa nd 3

- NO DISTINCT TAPROOT PRESENT.

Very fine sandy loa m

D

Fine sa nd

SITE I TOTAL AGE - 70 - CENTRAL AND LATERAL SINKERS SPARSE, DEVELOP HEIGHT - 75

PROGRESSIVELY. - MASSES OF FINE ROOTS IN EACH FINE TEXTURED STRATUM. - LATERALS EXTEND IN B TO 30 FT.

----- ---------

- NO DISTINCT TAPROOT PRESENT.

WHITE PINE

No.12

Ponded sands ...... --__ (Aeolia n cap) - �::='==--=====�AOA2

Loa m y medium and fine sand

B Medium a n d

fine s a nd

Medium and fine s a nd Fine sa nd and s ilt

Medium C and 8 fine sand o Fine sand and

_---------- _j S��rg �'t��ed

Medium and fine sa nd

___ ------

----- Silt loom, _ _ _ _ _ _ _ gleyed slightly

----- Medium and fine sa n d

- MODERATE NUMBER O F CENTRAL AND LATERAL SINKERS SITE r TOTAL AGE-70

HEIGHT -77 PRESENT WHICH DEVELOP PROGRESSIVELY.

- MASSES OF FINE ROOTS IN EACH FI NE TEXTURED STRATUM. - LATERALS EXTEND TO 30 FT.

4

2

3

4

SOILS WITH IMPEDING OBJECTS - MEDIUM TEXTURED, SOMEWHAT DRY

RED PINE

No. 13

- NO TAPROOT (LARGE BOULD E R BE LOW). SITE ill - SINK E RS MASSED ABOUT BOULDE R . - SHORT, THICKENED ROOTS COMMON I N UPPER C HORIZON. - LATE RALS WELL D E VE LOPE D EXTE NDING IN A AND B HORIZONS

TO 35 FT.

WHITE PINE

No.14

=========--- - -

Moulded Till

Loamy sand,

stony

B

Medium and fine sond,

stony

C

Loamy sand,

stony,

compact

TOTAL AGE - 75 HE IGHT -63

Moulded Till

B

Loamy sand

Medium and fine

C

sand

Loamy sond,

stony

- - - - - - - - - - - - -- Compact loamy sand,

2

3

4

2

3

4

stony 5

- NO TAPROOT. - SINKERS ARE NUME ROUS, E NDING IN MASS E S OF SHORT,

THICKE NE D FINE ROOTS AT UPPER C HORIZON. - LATERALS WELL DEVELOPED IN A AND B HORIZONS TO 35 FT.

16

SITE IT TOTAL AGE -75 HEIGHT -74

." ..

�

[