Skip to main content
U.S. flag

An official website of the United States government

Mechanical characteristics of the fine roots of two broadleaved tree species from the temperate Caspian Hyracanian Ecoregion


Azade Deljouei
Ehsan Abdi
Massimiliano Schwarz
Baris Majnounian
Hormoz Sohrabi



Publication type:

Scientific Journal (JRNL)

Primary Station(s):

Rocky Mountain Research Station


Forests. 11: 345.


In view of the important role played by roots against shallow landslides, root tensile force was evaluated for two widespread temperate tree species within the Caspian Hyrcanian Ecoregion, i.e., Fagus orientalis L. and Carpinus betulus L. Fine roots (0.02 to 7.99 mm) were collected from five trees of each species at three different elevations (400, 950, and 1350 m a.s.l.), across three diameter at breast height (DBH) classes (small = 7.5-32.5 cm, medium = 32.6-57.5 cm, and large =57.6-82.5 cm), and at two slope positions relative to the tree stem (up- and down-slope). In the laboratory, maximum tensile force (N) required to break the root was determined for 2016 roots (56 roots per each of two species x three sites x three DBH classes x two slope positions). ANCOVA was used to test the effects of slope position, DBH, and study site on root tensile force. To obtain the power-law regression coefficients, a nonlinear least square method was used. We found that: 1) root tensile force strongly depends on root size, 2) F. orientalis roots are stronger than C. betulus ones in the large DBH class, although they are weaker in the medium and small DBH classes, 3) root mechanical resistance is higher upslope than downslope, 4) roots of the trees with larger DBH were the most resistant roots in tension in compare with roots of the medium or small DBH classes, and 5) the root tensile force for both species is notably different from one site to another site. Overall, our findings provide a fundamental contribution to the quantification of the protective effects of forests in the temperate region.


Deljouei, Azade; Abdi, Ehsan; Schwarz, Massimiliano; Majnounian, Baris; Sohrabi, Hormoz; Dumroese, R. Kasten. 2020. Mechanical characteristics of the fine roots of two broadleaved tree species from the temperate Caspian Hyracanian Ecoregion. Forests. 11: 345.


Publication Notes

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.