The effects of different microwave energy densities (0, 60, 80, and 100 kWh/m³) on the gas permeability of sapwood and heartwood of radiata pine in the longitudinal, radial, and tangential directions were investigated. The multi-scale pore size distribution was systematically analyzed with various analytical methods. High intensity microwave (HIMW) treatment significantly improved the gas permeability of the wood in three directions, and the gas permeability was positively correlated with the microwave energy density. The gas permeability of the treated sapwood was 1.6–2.5 times higher, and that of the treated heartwood was more than 6 times higher than the untreated wood at the microwave energy density of 100 kWh/m³. The HIMW treatment significantly affected the pore size distribution. In the micropore–mesopore (< 50 nm) range, the surface area and average pore diameter of the treated sapwood samples were 10.68% and 17.12% higher, respectively, and the total pore volume was 31.50% lower than that of the untreated sample. However, the specific surface area and total pore volume of the heartwood samples were 14.92% and 26.06% lower, respectively, and the average pore diameter was 35.55% higher at the microwave energy density of 100 kWh/m³. Treated wood mainly had slit-shaped mesopores (< 10 nm). For macropores (> 50 nm), treated sapwood displayed 20.57% total pore volume increase and 11.66% porosity rise; treated heartwood showed 31.24% total pore volume rise and 20.78% porosity increment. Furthermore, SEM results showed HIMW treatment damaged weak structures like the compound middle lamella and ray parenchyma cells.

研究了不同微波能量密度（0、60、80和100 kWh/m ^{3 ）对辐射松边材和心材纵向、径向和切向透气性的影响。}采用多种分析方法对多尺度孔径分布进行了系统分析。高强度微波（HIMW）处理显着提高了木材三个方向的透气性，且透气性与微波能量密度呈正相关。^{在微波能量密度为100 kWh/m 3 时}，处理过的边材的透气性比未处理的木材高1.6~2.5倍，处理过的心材的透气性高6倍以上。HIMW处理显着影响孔径分布。在微孔-中孔（< 50 nm）范围内，处理后边材样品的表面积和平均孔径分别比未处理样品高10.68%和17.12%，总孔体积比未处理样品低31.50%。然而，在微波能量密度为100 kWh/m 3 时，心材样品的比表面积和总孔容分别降低了14.92%和26.06%，平均孔径提高了35.55% ^。。处理过的木材主要具有狭缝状中孔（<10 nm）。对于大孔（> 50 nm），经过处理的边材显示出总孔体积增加了 20.57%，孔隙率增加了 11.66%；处理后的心材显示总孔隙体积增加了 31.24%，孔隙率增加了 20.78%。此外，SEM 结果显示 HIMW 处理损坏了复合中层和射线薄壁细胞等弱结构。