A summary of property, plant and equipment, net is as follows (in thousands):


	December 31, 2022			December 31, 2021
Machinery and equipment	$	378,907		$	360,353
Buildings, improvements and leasehold improvements		70,816			75,374
Automobiles, trucks, tractors and trailers		6,376			6,450
Furniture and fixtures		19,373			19,668
Construction-in-progress		5,185			6,700
Land		26,695			28,671
Oil and gas producing assets		11,714			44,700
Total		519,066			541,916
Accumulated depreciation and depletion		(236,690	)		(185,642	)
Property, plant and equipment, net	$	282,376		$	356,274

We had $7.1 million and $7.2 million of leasehold improvements at December 31, 2022 and 2021, respectively. These leasehold improvements are depreciated over the shorter of the life of the asset or the term of the lease using the straight line method. Oil and gas producing assets include capitalized asset retirement costs associated with our oil and gas property.

Depreciation and depletion expense associated with our property, plant and equipment for the Current Period was $87.6 million. Depreciation and depletion expense, excluding depreciation related to assets held for sale, for the year ended for the Successor Period, Predecessor Period and the Prior Period was $209.7 million, $7.8 million and $108.0 million, respectively. See Note 17 - Discontinued Operations for a discussion of depreciation expense related to our discontinued operations.

As discussed above, depreciation expense in the Successor Period was impacted by the valuation process under fresh start accounting. Certain fully depreciated assets were assigned an estimated fair value of approximately $197.5 million and a remaining useful life of less than 36 months which significantly increased the amount of depreciation expense recorded in the Successor Period. Depreciation expense for these previously fully depreciated assets was $167.5 million for the Successor Period.

Gains and losses on disposals of assets are recognized within other (gains) and losses, net in our statement of operations. Prior to the Emergence Date, we recognized gains and losses on the disposal of assets within general and administrative expenses.

During the second quarter of 2022, changes in estimates regarding the timing and cost of decommissioning our oil and gas property under a reef-in-place program impacted the carrying value of our oil and gas producing assets. In accordance with ASC 410, the carrying value of our oil and gas producing assets, which included capitalized oil and gas reserves and capitalized asset retirement costs, was reduced by $38.2 million, which represented the net book value of all of our oil and gas assets at June 30, 2022.

As discussed above, due to revisions in estimates in both costs and timing of decommissioning the wells associated with our oil and gas property, at December 31, 2022, we recorded capitalized asset retirement costs of $11.1 million.