( ( ( Invest ( in ( a ( kerosene ( or ( propane heater ) ) ) ) ) ) ( if ( you ( ( do not ) ( have ( a ( fireplace ( or ( wood stove ) ) ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Invest) (PP (IN in) (NP (DT a) (NN kerosene) (CC or) (NN propane) (NN heater))) (SBAR (IN if) (S (NP (PRP you)) (VP (VBP do) (RB not) (VP (VB have) (NP (DT a) (NN fireplace) (CC or) (NN wood) (NN stove))))))) (. .)))
Invest in a  kerosene or propane heater if you do not have a fireplace or wood stove.
(ROOT (S (PP (RB Instead) (IN of) (NP (NN wood))) (, ,) (NP (DT some) (NNS fireplaces)) (VP (VBP use) (NP (NN propane))) (. .)))