Dr Mutua noted that more than 4.3 million trees are expected to be planted in the county this year.
The exercise comes as the county's tree cover stands at less than 4 per cent.
"We are planting trees not to see them but for our life," Mutua said.
The CS was accompanied by Tourism Principal Secretary John Olooltua and the county secretary Josphine Onunga.
Mutua was reacting to concerns raised by Governor Andrew Mwadime, who said that elephants and monkeys have become a major issue of concern in the region.
The leaders noted that wild animals have been invading people's settlement areas in search of water and pasture, and in the process, they destroy crops.
The CS promised that the government will effectively deal with the wildlife menace once and for all.
"We will deal with frequent elephant and monkey invasions into human settlement areas and ensure that the troublesome animals are moved out," he said.
Wundanyi MP Danson Mwashako and Woman Representative Lydia Haika, blamed marauding elephants and monkeys for food insecurity and poverty in the region.
Mwadime noted that even though over 62 per cent of the county land mass is occupied by Tsavo National Park, little is being ploughed back for rural development.
The governor, at the same time, accused the national government of delaying compensation for victims of wildlife attacks despite launching the payout in July this year.
Mwashako said monkeys have become a menace in the region grappling with persistent food shortages.
"The wild animals are eating food crops and compounding the already food insecurity in the region and should either be culled or translocated to other areas to minimize conflict," he said.
"The government can also use a scientific way of introducing family planning to these monkeys whose population is increasing at alarming levels," he added.
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