an interesting article but it would be nice to know what time scale these figures are worked at. Presumably they are annual figures but I think a mention of this would have been very useful.

These aren't annual figures. They represent the cumulative sequestration of carbon over hundreds or even thousands of years.

First a correction, the cited E regnans forest 2844tC/ha is actually CO2et/ha.

The av. annual seq. rate is only 8 tCO2/ha/an(2844tCO2/ha div. by 350 yrs)

Natural forests characteristically have low sequestration rates. Sadly they are inefficient for the urgent task of removing C02 from the atmosphere.

Old growth Rainforest sequestration rates:
Tasmanian 350yr E Regnans, 8 tCO2/ha/an
Amazon 350yr tropical 4 tC02/ha/an
NZ Kauri 1500yr 2 tC02/ha/an
Pacific NW D-fir 3 tC02/ha/an

Managed planted forest seq.rates can range from 40-80 tCO2/ha/an
Highest seq. rates occur in tropical hardwood plantations and require use of fertilisers.

There are two urgent tasks for global forestry, to protect existing forest carbon sinks (which take centuries to accumulate), and to utilise the rapid growth potential of managed forests to suck C02 from the atmosphere.

Mark Belton: The study says "C/ha" not "CO2/ha".

Annual sequestration rates aren't particularly relevant when you are talking about a situation where old-growth forest is replaced with plantation forest since the plantation forest will not store as much carbon as the old growth forest.