diff --git a/biogeochem/FatesAllometryMod.F90 b/biogeochem/FatesAllometryMod.F90
index d7e09393d4..94b58a881a 100644
--- a/biogeochem/FatesAllometryMod.F90
+++ b/biogeochem/FatesAllometryMod.F90
@@ -748,7 +748,8 @@ real(r8) function tree_lai( leaf_c, pft, c_area, nplant, cl, canopy_lai, vcmax25
           tree_lai = (log(exp(-1.0_r8 * kn * canopy_lai_above) - &
                kn * slat * leafc_per_unitarea) + &
                (kn * canopy_lai_above)) / (-1.0_r8 * kn)
-
+          ! precision errors in the above when leafc_per_unit_area is tiny can make treelai negative
+          tree_lai = max(0.0_r8,tree_lai)
           ! If leafc_per_unitarea becomes too large, tree_lai becomes an imaginary number 
           ! (because the tree_lai equation requires us to take the natural log of something >0)
           ! Thus, we include the following error message in case leafc_per_unitarea becomes too large.
@@ -774,7 +775,8 @@ real(r8) function tree_lai( leaf_c, pft, c_area, nplant, cl, canopy_lai, vcmax25
                kn * slat * leafc_slamax) + &
                (kn * canopy_lai_above)) / (-1.0_r8 * kn)) + &
                (leafc_per_unitarea - leafc_slamax) * sla_max
-
+          ! precision errors in the above when leafc_per_unit_area is tiny can make treelai negative
+          tree_lai = max(0.0_r8,tree_lai)
           ! if leafc_slamax becomes too large, tree_lai_exp becomes an imaginary number 
           ! (because the tree_lai equation requires us to take the natural log of something >0)
           ! Thus, we include the following error message in case leafc_slamax becomes too large.