  We study multiplicity correlations of hadrons in forward and backward
hemispheres in $pp$ inelastic interactions at energies 200GeV $\leq \sqrt{s}
\leq$ 13TeV within the microscopic quark-gluon string model. The model
correctly describes (i) the almost linear dependence of average multiplicity in
one hemisphere on the particle multiplicity in other hemisphere in the
center-of-mass frame; (ii) the increase of the slope parameter $b_{corr}$ with
rising collision energy; (iii) the quick falloff of the correlation strength
with increase of the midrapidity gap; (iv) saturation of the forward-backward
correlations at very high multiplicities. Investigation of the sub-processes on
partonic level reveals that these features can be attributed to short-range
partonic correlations within a single string and superposition of several
sub-processes containing different numbers of soft and hard Pomerons with
different mean multiplicities. If the number of Pomerons in the event is fixed,
no forward-backward correlations are observed. Predictions are made for the top
LHC energy $\sqrt{s} = 13$TeV.
