I would say that plants that increase SLA for drought adaptation like for cronic water shortage usually are better performers in frost tolerance. Their sugar content is probably higher, vacuoles small and osmotic adaptation may depress freezing point of a few degrees. Ice is not formed then, and this is more avoidance than tolerance Avoidance of freezing is linked to water adhesive forces and this may be relative to different factors like Ca+2, pectates and phosholipidic wall composition. I suggest to apply generic models to specific issues like what temperature treatment and for how long on a set of variants in a species. 

Freezing stress can be compared to drought/osmotic stress. To the best of my knowledge plants adapted or tolerant to freezing stress should have smaller SLA. Accordingly, plants growing under natural freezing or low temperatures show small leaves, leaves in the form of needles or spines with thick cuticle, sunken stomata etc. Hence, leaf area to dry weight ratio is low in plants that exist under natural freezing environments. Higher the leaf area more would be water content and accordingly higher susceptibility to freezing/osmotic/drought stress. However, if cells of these leaves possess higher level of compatible solutes (such as proline, glycinebetaine, sugars etc.) and/or cryoprotectants (many of the compatible solutes can be cryoprotectants). In summary, lower the SLA more would be freezing tolerance.

Freezing tolerance is expected to be negatively correlated to SLA. This may be inferred from greater freezing tolerance of the northern population (low SLA) than southern population (high SLA) of some sp in boreal region with consistency with SLA.

See

Lu et al 2003. Geographic variation in cold hardiness among eastern white pine (Pinus strobus L.) provenances in Ontario (DOI: 10.1016/S0378-1127(02)00481-4)

Hi Robbert, I think following links could be of help!

1) http://www.ejbiotechnology.info/index.php/ejbiotechnology/article/view/v13n1-10/1069

Coopman et al. (2010) Genotypic variation in morphology and freezing resistance of Eucalyptus globulus seedlings subjected to drought hardening in nursery. Electronic Journal of Biotechnology. DOI:  10.2225/vol13-issue1-fulltext-10 

2) www.unav.edu/.../EEB%2055%20305%20a%20314_%20Hekneby.pdf

Hekneby et al. (2006) Frost resistance and biochemical changes during cold

acclimation in different annual legumes. Environmental and Experimental Botany. DOI: 10.1016/j.envexpbot.2004.11.010

Dear Lahcen and followers, as suggested by literature we can not draw universal laws about SLA that is a morphological trait and freezing tolerance. It seems that in Pinus strobus this trait is correlated in a reversed way to tolerance, and this is quite a sport, but it is a specific finding, possibly linked to covariance with some deterministic metabolic arrangement. It is up to you to search for the target between osmotic potential, surface tension and a set of possible substances that are in conifers. I would check first if ice is formed at all when leaves are subjected to freezing tempperature in a cabinet. If the exotherm is delayed or absent please check for freezing avoidance. Olien in  gave the thermodynamics of freezing formalism 

Olien CR.

J Theor Biol. 1973 Apr;39(1):201-10.

s 

Dear Bonji

I agree with you, there is no universal correlation between SLA (1/LMA) and freezing tolerance.

My point is that in some region, freezing tolerance is associated to an increase in leaf density (through the accumulation of Non-structural carbohydrates) and  a decrease in SLA.

Dear all

Another interesting article to see

Perez et al 2014. Decoupled evolution of foliar freezing resistance,temperature niche and morphological leaf traits in Chilean Myrceugenia. Journal of Ecology. 102:972–980

Does the number of leaves realted to cold resistance/ tolerance

I thing that  is SLA that dimishid with freezing. But also higs SLA could be a better performance for avoiding greezing

Thank you very much for your answers and suggestions of publicaitons, they have proven extremely useful!