Variation of cork porosity along the stem in harvested cork oak (Quercus suber L.) trees

Abstract

& Key message Cork porosity, due to lenticular channels, varied along the stem of Quercus suber L. Lenticular channels' area, rather than their number, decreased upwards along the stem. Area decrease was observed regardless of tree size and of its intrinsic porosity. & Context The cork of Quercus suber L. is radially crossed by lenticular channels, defining cork's natural porosity. It has been suggested that porosity decreases from the stem base upwards, but studies on such variation have not yet been presented. & Aims Three main research questions were addressed: (i) how large is the variation of cork porosity upwards along the stem; (ii) how does porosity variation relate with porosity traits, namely the size and number of lenticular channels and (iii) how much does porosity vary with stem height and between trees. & Methods We set up a study at tree level to quantify the porosity of cork samples from fixed stem heights. Our statistical modelling approach was based on linear mixed-effects models, given the nested structure of the data. In the model fitting, porosity was described as a function of tree stem height, while the random effects explained the source of variability introduced by different tree size (as given by stem diameter at breast height, D bh ) and porosity (as given by intrinsic porosity, CP bh ). & Results The lenticular channels' area rather than their number consistently decreased up the stem. The area proportion of the lenticular channels in the cork tissue (i.e. porosity coefficient) decreased by about 1.4% per metre upwards along the stem, regardless of tree size and of its porosity. & Conclusion Our findings highlight that the lenticular channels' traits greatly vary among trees, much more than within-tree, which may be an important clue to predict variations in cork properties, for decision-making on cork oak management.

Is Cork Growth a Reliable Proxy for Stem Diameter Growth in Cork Oak (Quercus suber L.)? Implications for Forest Management under Climate Change in Mediterranean Regions

“…Section 2.1), which probably had a negative impact on cambium activity, much more influenced by the climatic factors prevailing in the current growth season (Figure 3). Trees might use (less) current photosynthates to support this cambial activity [27] because the "non-cork" (wood) growth probably competes with other carbon sinks namely with reproduction efforts [7,11,28,29].…”

Cork derived laser-induced graphene for sustainable green electronics

“…Similar to a beehive, cork has cells with pentagonal and hexagonal hollow structures [35,36], which provides a large surface area to induce porous 3D structures. Furthermore, it presents extraordinary properties, such as lightweight, biodegradability, compressibility, impermeability, resistance to high temperatures, and thermal insulation [37,38]. Therefore, the possibility of widespread adoption of LIG electrodes in novel flexible and wearable devices could lead to the further development of self-sustainable platforms.…”