Determination of nuclear magnetic resonance surface relaxivity for the macropore system from wood cell lumen

Journal of Wood Science

Official Journal of the Japan Wood Research Society

Table 1 The pore sizes of some specific structural elements in wood [11,12,13]

Wood species	Structural elements	Pore size	Pore scale
Spruce	Cell wall pores (wetted)	0.4–40 nm	Micro-mesopore
–	Cell wall pores (wetted)	1–10 nm	Micro-mesopore
–	Inter-microfibril spaces	2–4.5 nm	Mesopore
Softwoods	Cell wall pores (dried)	2–100 nm	Meso-macropore
Ring porous hardwoods	Cell wall pores (dried)	2–100 nm	Meso-macropore
Diffuse porous hardwoods	Cell wall pores (dried)	2–100 nm	Meso-macropore
Softwoods	Pit membranes of bordered pits	10 nm-8 μm	Meso-macropore
Softwoods	Pit apertures of bordered pits	400 nm-6 μm	Macropore
Hardwoods	Lumens of fibers	1–30 μm	Macropore
Softwoods	Pit chamber apertures of bordered pits	4–30 μm	Macropore
Hardwoods	Alternate pits	5–170 μm	Macropore
Softwoods	Lumens of tracheid	10–50 μm	Macropore
Ring porous hardwoods	Lumens of vessels	20–400 μm	Macropore
Softwoods	Resin canals	30–300 μm	Macropore
Diffuse porous hardwoods	Lumens of vessels	40–250 μm	Macropore

The microscopic pore size is < 2 nm, mesoscopic pore size is 2–50 nm, and macroscopic pore size is > 50 nm